Therapeutic vaccination reverses severe canine leishmaniasis: a case report

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Naucke This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7886906/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background: Treatment of canine leishmaniasis (CanL), a severe infection caused by L. infantum , is often challenging, e.g. fails due to the development of resistance of the pathogen to the medication and/or has severe side effects. Alternative treatment e.g. the use of immunomodulators has also been suggested and is already applied. Findings: Here, we report a case of a dog naturally infected by CanL, that was clinically in a severe life-threatend situation. The dog was vaccinated by a single dose of Letifend® and the dog recovered surprisingly well, within a couple of weeks. The clinical profile as well as parameters of clinical chemistry were recorded. Conclusions: Our results suggest that: 1) Vaccination with Letifend® can be used successfully to treat leishmaniasis. A surprisingly rapid improvement in the dog's general condition was observed 2) Also laboratory parameters that are recorded long-term become normalized. Dog Leishmaniasis therapy Vaccination immunomodulation Letifend® Figures Figure 1 Figure 2 Figure 3 Main text Canine leishmaniasis (CanL), caused by Leishmania infantum , poses ongoing therapeutic challenges in veterinary medicine, particularly in endemic regions such as Southern Europe, South America, and parts of Asia [ 1 , 2 ]. The disease is transmitted by phlebotomine sandflies and manifests as a systemic infection that can lead to severe, life-threatening conditions if left untreated. CanL is characterized by its complex pathophysiology, chronic progression, and high relapse rates, making treatment particularly difficult. Therapeutic strategies for CanL differ substantially between endemic and non-endemic areas. In endemic regions, such as Southern Europe, South America, and parts of Asia, the preferred therapy involves the use of leishmanicidal drugs. These include antimonial drugs, such as meglumine antimoniate and miltefosine, an alkylphosphocholine originally developed as an antineoplastic agent. Both exhibit significant antileishmanial activity and are the preferred drugs in all Mediterranean countries for the treatment of CanL, as a rule administered in combination with the leishmaniostatic drug allopurinol, a purine analogue that inhibits parasite replication. Leishmanicidal drugs aim to reduce the parasite load and manage the disease more aggressively. This approach is essential to decrease the amastigote load in the dog, thereby reducing the risk of transmission to other animals and humans [ 3 ]. However, these treatments are frequently associated with severe side effects, including nephrotoxicity, hepatotoxicity, pancreatitis and gastrointestinal distress [4–7]. Moreover, increasing reports of drug resistance in Leishmania infantum have raised concerns about the long-term efficacy of treatments using meglumine antimoniate or miltefosine [ 8 – 10 ]. In non-endemic areas, the emphasis is on using leishmaniostatic drugs, particularly when typical clinical manifestations are absent. Allopurinol is commonly used as a first-line treatment in these regions due to its ability to inhibit parasite replication without the same level of toxicity associated with leishmanicidal drugs. Allopurinol aims to maintain a balance between controlling the infection and minimizing adverse effects, especially given the lower risk of reinfection in non-endemic areas. However, long-term administration may also be problematic here, as there is a risk of developing xanthine urolithiasis [ 11 , 12 ] and contribute to drug resistance [ 13 , 14 ]. Alternative treatments may include herbal remedies, such as chamomile ( Matricaria chamomilla ) and artemisinin, which have shown antileishmanial properties. Artemisinin, a sesquiterpene lactone primarily used in malaria treatment, has shown potential in reducing parasite loads in experimental settings [ 15 ]. Similarly, α-bisabolol, a natural monocyclic sesquiterpene alcohol found in chamomile has been identified as a potent inhibitor of Leishmania promastigotes and amastigotes [ 16 ]. While these alternative treatments demonstrate preclinical efficacy, they require further clinical validation before they can be widely adopted as part of standard CanL treatment protocols. Given the limitations of conventional drug therapies, immunomodulatory approaches have gained increasing attention in CanL management. Rather than targeting the parasite directly, these treatments aim to enhance the host's immune response to control infection and prevent disease progression. One of the most well-known immunomodulators in veterinary medicine is domperidone, a dopamine D₂ receptor antagonist that stimulates prolactin secretion, which in turn modulates cell-mediated immunity. Prolactin enhances macrophage activation and promotes the Th1 immune response, which is critical for controlling Leishmania infections. Studies have shown that domperidone can reduce the severity of clinical signs in infected dogs and may help prevent disease progression [ 17 – 20 ]. However, it is most effective in early-stage infections or as a prophylactic measure in dogs at high risk of exposure. Another promising immunomodulator is impromune, a nutraceutical formulation that contains Nucleoforce® (nucleotide-based immunostimulant) and AHCC® (active hexose correlated compound, derived from mushrooms). These components enhance the function of NK cells and macrophages, leading to an improved Th1 immune response. Clinical studies have suggested that impromune can help maintain immune homeostasis and support the recovery of infected dogs, particularly when used in combination with antiparasitic drugs [ 21 , 22 ]. While vaccination has traditionally been used as a prophylactic measure, recent studies suggest that it may also possess therapeutic potential in CanL management [ 23 – 26 ]. Several vaccines [27,28] have been developed to induce protective immunity against L. infantum , with Letifend® being one of the most promising candidates [ 29 ]. Letifend® is a recombinant protein-based vaccine that contains Q protein as active ingredient, that stimulates the Th1 immune response resulting in a long-lasting cellular and humoral response and activation in macrophages to produce nitric oxide radicals which are crucial for controlling Leishmania infections [ 30 ]. After experimental infection, Letifend®-vaccinated dogs showed a lower intensity of clinical symptoms [ 31 ]. The vaccine demonstrated 72% efficacy (95% CI: 65–79%) in preventing clinical CanL in controlled trials [ 32 ]. Thus, the vaccine was granted a marketing authorization for valid throughout the European Union in 2016 [ 33 , 34 ]. Generally, Letifend® is indicated for the immunization of non-infected dogs from six months of age to reduce the risk of developing an active infection and/or clinical disease after exposure to L. infantum [ 35 ]. In addition to its role in disease prevention, there is emerging evidence that therapeutic vaccination with Letifend® may enhance the immune response in already infected dogs, potentially leading to clinical improvement. The case In this case report, we present a dog suffering from severe, life-threatening CanL that exhibited an unexpectedly rapid clinical recovery following a single-dose vaccination with Letifend®. Over the course of a few weeks, the dog's clinical condition improved dramatically, and laboratory parameters normalized, indicating a potential immunotherapeutic effect of the vaccine. Our findings suggest that vaccination with Letifend® could represent a novel therapeutic strategy for CanL, particularly in cases where conventional therapies are ineffective or associated with severe side effects. These results highlight the need for further clinical studies to explore the immunomodulatory effects of vaccination in CanL treatment. If confirmed in larger cohorts, therapeutic vaccination could revolutionize CanL management, offering a safer and more effective alternative to traditional drug-based therapies. In Summer 2021, a male mixed-breed dog, approximately three years old, was found in a critical condition near a roadside in a remote part of Sardinia. The dog was very lethargic, strongly dehydrated and severely anemic, displaying extreme weakness and pale mucous membranes. Upon closer examination, the dog was found to be infested with at least 15 ticks of the species R. sanguineus . The presence of this tick species raised immediate concern for vector-borne infections, as R. sanguineus is a known carrier of multiple hemopathogens. Upon arrival in an animal shelter, the dog received supportive care, including fluid therapy, hematinic supplements, and antimicrobial treatment with doxycycline (10 mg/kg, PO, SID for 28 days). The decision to administer doxycycline was driven by its broad-spectrum efficacy against Ehrlichia spp., Anaplasma spp ., and other bacterial pathogens commonly transmitted by R. sanguineus , with its effectiveness being highest during the acute phase of infection. Over the following weeks, the dog gradually recovered, showing significant clinical improvement. Follow-up hematological tests revealed stabilized erythrocyte levels within the normal range, and the dog regained weight and strength. However, systematic screening for vector-borne diseases was omitted at the time. Several months later, the dog developed signs of urinary discomfort, leading to further diagnostics. A large struvite-type bladder stone was identified via ultrasound and subsequently removed. Following this intervention, the dog remained clinically stable. However, due to the lack of systematic screening for vector-borne infections at initial presentation, potential chronic infections such as subclinical ehrlichiosis or leishmaniasis, could not be ruled out. In April 2022 a family was found for the dog and it was transferred to Germany. Due to the above-mentioned history, it underwent a thorough veterinary examination to check for infectious diseases common in the Mediterranean region. Clinical laboratory parameters were evaluated. The following analytical methods were applied to the blood and urine samples. Blood Cell Analysis: Complete blood counts were determined using EDTA-anticoagulated whole blood samples analyzed with the scil Vet abc Plus + automated hematology analyzer (scil Animal Care Company, Viernheim, Germany). This fully automated system employs impedance technology and flow cytometry to quantify erythrocyte, leukocyte, and platelet parameters. Serum Capillary Electrophoresis: Serum protein electrophoresis was performed using the MINICAP FLEX-PIERCING system (Sebia, Lisses, France). This capillary electrophoresis technique separates serum proteins into six fractions (albumin, α1-, α2-, β1-, β2- and γ-globulins) based on their electrophoretic mobility under alkaline conditions. Urinalysis was performed using IDEXX UA test strips and the IDEXX VetLab UA point-of-care urine chemistry analyser (IDEXX Laboratories, Westbrook, ME, USA) Immunofluorescence Antibody Test (IFAT): Anti- Leishmania infantum antibody titers were determined using a semi-quantitative IFAT MegaFLUO® LEISH Kit (MEGACOR Diagnostik GmbH, Hörbranz, Austria). Serum samples were serially diluted (1:50, 1:100, 1:200, 1:500, 1:1000, 1:2000, 1:4000, and 1:8000) and applied to slides pre-coated with L. infantum promastigotes. After 30 minutes of incubation at room temperature, the slides were washed (5 minutes with phosphate-buffered saline) and treated with fluorescein-labeled conjugate (30 minutes, in the dark). Following a final wash, the slides were mounted and examined under a Nikon Eclipse 80i fluorescence microscope equipped with an FITC filter set (excitation: 465–495 nm, dichroic mirror: 505 nm, emission: 515–555 nm) and a 100 W mercury vapor lamp (Osram HBO 103 W/2) at 400× magnification. Positive samples showed distinct yellow-green fluorescence on the cytoplasmic membrane at a cut-off dilution of 1:100. Negative samples exhibited either gray coloration without fluorescence or aberrant fluorescence patterns. Fluorescence on the flagella of promastigotes was also assessed as negative. The dog was tested positive for L. infantum with a titer of 1:4000. Hematology showed lymphopenia, anemia, and thrombocytopenia (see Table 1 ). Allopurinol (2 x 5 mg/kg BID) was initiated, but the dog deteriorated markedly, developing anorexia, diarrhea, and worsening anemia. Unfortunately, the dog's general condition deteriorated markedly over the following weeks. It stopped eating and drinking voluntarily, developed diarrhea, and experienced a further increase in anemia, indicated by pale mucous membranes. The dog became very apathetic and lethargic, only leaving its resting place to vomit. Table 1 Laboratory parameters recorded at time 0 (T0) and after 6 (T6), 12 (T12), and 24 (T24) month after diagnosis Substrate Parameter T0 T6 T12 T24 Normal range Serum* Total protein (g/L) 83.6 67.2 67.9 79.0 54.0–75.0 Alb/Glob ratio 0.4 1.0 1.1 1.0 > 0.6 Gamma globulin (g/L) 24.1 59.9 12.4 30.9 12.7 33.1 16.5 41.9 < 45 Beta 2 globulin (g/L) 13.0 6.7 6.7 8.7 Beta 1 globuloin (g/L) 13.1 4.2 4.7 7.7 Alpha 2 globulin (g/L) 4.9 4.2 5.2 5.3 Alpha 1 globulin (g/L) 4.8 3.4 3.8 3.7 Albumin (g/L) 23.8 34.4 34.8 37.9 25.0–44.0 IFAT-titer Leishmania 1:4000 1:1000 1:2000 1:4000 negative Blood WBC (10 3 /µL) 4.3 9.3 8.1 6.6 6.0–12.0 RBC (10 6 /mL) 3.9 5.7 6.0 6.3 5.5–8.5 HB (g/dL) 8.9 15.4 15.6 15.2 15.0–20.0 HcT (%) 25.1 44.1 44.6 45.7 44.0–57.0 PLT (K/µL) 98.0 237 202 229 200–460 Urin Ery (Ery/µL) 30 negative negative negative negative Protein (mg/L) 250 negative negative negative negative * All measured serum concentrations of creatinine and urea remained within the normal range throughout the entire period. Due to potential side effects of typical leishmanicidal drugs, it was decided that it should not receive classic therapy with leishmanicidal medication due to its serious state of health. Instead, the dog was administered a single dose of Letifend® with the intention of giving it the fastest and most effective immune response possible to combat the pathogen. According to the “veterinary medicinal products regulation” this alternative treatment option, the so-called “cascade system”, permitting off-label use when standard therapies fail or is considered to be non-effective [ 36 , 37 ]. In fact, the decision did not pose a major concern as the manufacturer did not consider there to be any risk to infected dogs. Rather, it is stated that the vaccine can be used safely in infected dogs. Also, booster vaccination of infected dogs did not worsen the course of the disease [ 38 , 39 ] At this point in time, the dog was fed a watery mash of its favorite food. After just 10 days, its general condition improved, and within three weeks, it showed almost normal activity. Exercise tolerance normalized, allowing unrestricted activity (> 3 km/day). The laboratory values presented in Table 1 demonstrate that immunomodulation with Letifend® produced a sustained effect. Notably, the rising albumin/globulin ratio clearly indicates a swift and effective shift to a cellular Th1 immune response, efficiently countering the pathogens. Subsequently, the course of the health status and of the laboratory values were monitored over a period of 2 years. The serum protein capillary electrophoreses in Fig. 2 show a gradual lowering of the gamma-fraction over time, indicating a decrease of the non-protective IgG, that can substantially contribute to disease progression through the formation of pathogenic immune complexes by the respective IgG with circulating antigens [ 40 ]. During this period, no further therapeutic actions were taken to treat the leishmaniasis. Only two years after the Letifend® administration, the laboratory parameters showed mild deterioration and an allopurinol / domperidone therapy was started, which has been successfully continued to the present day, according to a staged protocol, as recommended for non-endemic areas." [ 41 ]. The dog is still clinically healthy with regard to the L. infantum infection. This case highlights the complexity of diagnosing and managing vector-borne diseases in rescued dogs, particularly those originating from endemic regions such as Sardinia. The absence of systematic serological or molecular screening at the time of rescue resulted in an undiagnosed chronic L. infantum underscores the necessity of comprehensive diagnostic protocols for rescued dogs, even in the absence of overt clinical symptoms at the time of admission. The dog’s rapid deterioration following its relocation to Germany revealed the progressive nature of untreated leishmaniasis. Despite the initiation of standard allopurinol therapy, the dog's condition continued to decline, necessitating an alternative approach. The therapeutic administration of a single dose of the Letifend® vaccine resulted in a remarkably rapid and sustained clinical improvement, with stabilized laboratory parameters and a marked shift towards a protective Th1 immune response. The case suggests that therapeutic vaccination with Letifend® may play a crucial role in modulating immune responses in dogs with clinical leishmaniasis, potentially offering an alternative or complementary approach to conventional treatments. The observed long-term immunomodulatory effect further supports the hypothesis that vaccination could enhance host immune control of L. infantum infections. It must be assumed that the effectiveness of the therapeutic use of Letifend® depends on a number of factors, such as genetics, breed, immune status and phase of the disease, that are still relatively unknown. Therefore, the use of Letifend® is currently not a generally applicable alternative for the treatment of leishmaniasis, but in individual cases it can actually be life-saving. Attention must also be paid to the fact that mild deterioration of laboratory values two years post-vaccination emphasizes the need for long-term monitoring and, in some cases, the reintroduction of adjunctive therapies such as allopurinol and domperidone to maintain disease control. This case highlights the promising potential of Letifend® as a therapeutic option, suggesting that further research is needed to understand its role in managing CanL, especially in dogs with established infections where conventional treatments might fall short. The evidence supports the need for more investigation into its effectiveness in such cases. Abbreviations Alb Albumin CanL Canine leishmaniasis EDTA Ethylenediaminetetraacetic acid Ery Erythrocytes FITC Fluorescein isothiocyanate Glob Globulin Hb Hemoglobin HcT Hematocrit IFAT Immunofluorescence antibody test IgG Immunoglobulin G NK Natural killer PLT Platelet count RBC Red blood cell count Th1 T helper 1 cells WBC White blood cell count RBC Red blood cell count Declarations Ethics approval and consent to participate No ethical approval was required. Consent for publication Not applicable. Competing interests The authors declare no competing interests. Author details (optional) MR: [email protected] TN: [email protected] TW: [email protected] Funding This research received no specific grant from any funding agency in the public, commercial, or not for profit sectors. Author Contribution The dog featured in this report, owned by TW, was under the care of MR, who performed all clinical examinations and treatments. All procedures were conducted in consultation and agreement with all authors. Laboratory analyses were carried out by TN and MR, with TN specifically responsible for the microscopic examination and serum electrophoresis. TW wrote the manuscript, and all authors reviewed, read, and approved the final version. Acknowledgement We thank the employees of the animal shelter "I Fratelli Minori" of the non-profit organization LIDA in Olbia (Italy) for providing all the information about the dog in the study. Availability of data and materials All available data generated during this study are included in the published article. References Priolo V, Ippolito D, Rivas-Estanga K, De Waure C, Martínez-Orellana P. Canine leishmaniosis global prevalence over the last three decades: a meta-analysis and systematic review. Comparative Immunology, Microbiology and Infectious Diseases. 2024; 112:102211. https://doi.org/10.1016/j.tvjl.2006.10.019 Morales-Yuste M, Martín-Sánchez J, Corpas-Lopez V. Canine leishmaniasis: Update on epidemiology, diagnosis, treatment, and prevention. Veterinary Sciences. 2022; 9(8):387. https://doi.org/10.3390/vetsci9080387 Solano-Gallego L, Miró G, Koutinas A, Cardoso L, Pennisi MG, Ferrer L, Bourdeau P, Oliva G, Baneth G, The LeishVet Group. LeishVet guidelines for the practical management of canine leishmaniosis. Parasit Vectors. 2011; 4:86. https://doi.org/10.1186/1756-3305-4-86 Woerly V, Maynard L, Sanquer A, Eun HM. Clinical efficacy and tolerance of miltefosine in the treatment of canine leishmaniosis. Parasitol Res. 2009; 105:463–9. https://doi.org/10.1007/s00436-009-1404-2 Mateo M, Maynard L, Vischer C, Bianciardi P, Miró G. Comparative study on the short term efficacy and adverse effects of miltefosine and meglumine antimoniate in dogs with natural leishmaniosis. Parasitol Res. 2009; 105:155–62. https://doi.org/10.1007/s00436-009-1375-3 Moritz A, Steuber S, Greiner M. Clinical follow-up examination after treatment of canine leishmaniasis. Tokai J Exp Clin Med. 1998; 23:279 – 83. [7] Viñeta C, Castro J, López MC, Frau M, Costas A, Arenas C, Roura X. Is pancreatitis associated with meglumine antimoniate treatment for canine leishmaniosis? A multicentric prospective study. Parasit Vectors. 2024; 17:532. https://doi.org/10.1186/s13071-024-06617-7 Gizzarelli M, Foglia Manzillo V, Inglese A, Montagnaro S, Oliva G. Retrospective Long-Term Evaluation of Miltefosine-Allopurinol Treatment in Canine Leishmaniosis. Pathogens. 2023; 12:864. https://doi.org/10.3390/pathogens12070864 Ashutosh, Sundar S, Goyal N. Molecular mechanisms of antimony resistance in Leishmania . J Med Microbiol. 2007; 56:143 – 53. https://doi.org/10.1099/jmm.0.46841-0 Moncada-Diaz MJ, Rodríguez-Almonacid CC, Quiceno-Giraldo E, Khuong FTH, Muskus C, Karamysheva ZN. Molecular Mechanisms of Drug Resistance in Leishmania spp. Pathogens. 2024; 27;13:835. https://doi.org/10.3390/pathogens13100835 Jesus L, Arenas C, Domínguez-Ruiz M, Silvestrini P, Englar RE, Roura X, Leal RO. Xanthinuria secondary to allopurinol treatment in dogs with leishmaniosis: Current perspectives of the Iberian veterinary community. Comp Immunol Microbiol Infect Dis. 2022; 83:101783. https://doi.org/10.1016/j.cimid.2022.101783 Torres M, Bardagí M, Roura X, Zanna G, Ravera I, Ferrer L. Long term follow-up of dogs diagnosed with leishmaniosis (clinical stage II) and treated with meglumine antimoniate and allopurinol. Vet J. 2011;188:346–51. https://doi.org/10.1016/j.tvjl.2010.05.025 Yasur-Landau D, Jaffe CL, Doron-Faigenboim A, David L, Baneth G. Induction of allopurinol resistance in Leishmania infantum isolated from dogs. PLoS Negl Trop Dis. 2017;11:e0005910. https://doi.org/10.1371/journal.pntd.0005910 Schäfer I, Faucher M, Nachum-Biala Y, Ferrer L, Carrasco M, Kehl A, Müller E, Naucke TJ, Baneth G. Evidence for in vivo resistance against allopurinol in a dog infected with Leishmania infantum by reduction in copy numbers of the S-adenosylmethionine synthetase (METK) gene. Parasit Vectors. 2024; 17:506. https://doi.org/10.1186/s13071-024-06583-0 Medkour H, Bitam I, Laidoudi Y, Lafri I, Lounas A, Hamidat HK, Mekroud A, Varloud M, Davoust B, Mediannikov O. Potential of Artesunate in the treatment of visceral leishmaniasis in dogs naturally infected by Leishmania infantum : Efficacy evidence from a randomized field trial. PLoS Negl Trop Dis. 2020;14:e0008947. https://doi.org/10.1371/journal.pntd.0008947 Corpas-López V, Merino-Espinosa G, Acedo-Sánchez C, Díaz-Sáez V, Navarro-Moll MC, Morillas-Márquez F, Martín-Sánchez J. Effectiveness of the sesquiterpene (-)-α-bisabolol in dogs with naturally acquired canine leishmaniosis: an exploratory clinical trial. Vet Res Commun. 2018; 42:121–130. https://doi.org/10.1007/s11259-018-9714-4 Cavalera MA, Gernone F, Uva A, D'Ippolito P, Roura X, Paltrinieri S, Zatelli A. Effect of domperidone (leisguard®) on antibody titers, inflammatory markers and creatinine in dogs with leishmaniosis and chronic kidney disease. Parasit Vectors. 2021; 14:525. https://doi.org/10.1186/s13071-021-05030-8 Cavalera MA, Gernone F, Uva A, Donghia R, Zizzadoro C, Zatelli A. Efficacy of domperidone plus renal diet in slowing the progression of chronic kidney disease in dogs with leishmaniosis. Parasit Vectors. 2022; 15:397. https://doi.org/10.1186/s13071-022-05537-8 Sabaté D, Llinás J, Homedes J, Sust M, Ferrer L. A single-centre, open-label, controlled, randomized clinical trial to assess the preventive efficacy of a domperidone-based treatment programme against clinical canine leishmaniasis in a high prevalence area. Prev Vet Med. 2014; 115:56–63. https://doi.org/10.1016/j.prevetmed.2014.03.010 Baxarias M, Donato G, Mateu C, Salichs M, Homedes J, Miró G, Pennisi MG, Solano-Gallego L. A blinded, randomized and controlled multicenter clinical trial to assess the efficacy and safety of Leisguard® as an immunotherapeutic treatment for healthy Leishmania infantum -seropositive dogs. Parasit Vectors. 2023; 16:344. https://doi.org/10.1186/s13071-023-05903-0 Segarra S, Miró G, Montoya A, Pardo-Marín L, Teichenné J, Ferrer L, Cerón JJ. Prevention of disease progression in Leishmania infantum -infected dogs with dietary nucleotides and active hexose correlated compound. Parasit Vectors. 2018; 11:103. https://doi.org/10.1186/s13071-018-2705-z Miró G, Segarra S, Cerón JJ, Ferrer L, Solano-Gallego L, Montell L, Costa E, Teichenne J, Mariné-Casadó R; GALILEI trial Group; Roura X. New immunomodulatory treatment protocol for canine leishmaniosis reduces parasitemia and proteinuria. PLoS Negl Trop Dis. 2024; 18:e0012712. https://doi.org/10.1371/journal.pntd.0012712 Roatt BM, Aguiar-Soares RD, Reis LE, Cardoso JM, Mathias FA, de Brito RC, da Silva SM, Gontijo NF, Ferreira SA, Valenzuela JG, Corrêa-Oliveira R, Giunchetti RC, Reis AB. A Vaccine Therapy for Canine Visceral Leishmaniasis Promoted Significant Improvement of Clinical and Immune Status with Reduction in Parasite Burden. Front Immunol. 2017;8:217. https://doi.org/10.3389/fimmu.2017.00217 Coelho, E.A.F., Christodoulides, M. (2023). Vaccines for Canine Leishmaniasis. In: Christodoulides, M. (eds) Vaccines for Neglected Pathogens: Strategies, Achievements and Challenges. Springer, Cham. https://doi.org/10.1007/978-3-031-24355-4_13 Elsheikha, Hany. "Leishmaniosis in canines: part 1–treating and controlling infection." 2016: 20163118985. https://www.vettimes.co.uk/app/uploads/wp-post-to-pdf-enhanced-cache/1/leishmaniosis-in-canines-part-1-treating-and-controlling-infection.pdf Nascimento LFM, Miranda DFH, Moura LD, Pinho FA, Werneck GL, Khouri R, Reed SG, Duthie MS, Barral A, Barral-Netto M, Cruz MSP. Allopurinol therapy provides long term clinical improvement, but additional immunotherapy is required for sustained parasite clearance, in L. infantum -infected dogs. Vaccine X. 2019; 4:100048. https://doi.org/10.1016/j.jvacx. 2019.100048 [27] Velez R, Gállego M. Commercially approved vaccines for canine leishmaniosis: a review of available data on their safety and efficacy. Trop Med Int Health. 2020;25:540–557. https://doi.org/10.1111/tmi.13382 Shital S, Madan E, Selvapandiyan A, Kumar Ganguly N. An update on recombinant vaccines against leishmaniasis. Indian J Med Res. 2024;160:323–337. https://doi.org/10.25259/IJMR_1040_2024 Fernández Cotrina J, Iniesta V, Monroy I, Baz V, Hugnet C, Marañon F, Fabra M, Gómez-Nieto LC, Alonso C. A large-scale field randomized trial demonstrates safety and efficacy of the vaccine LetiFend® against canine leishmaniosis. Vaccine. 2018;36:1972–1982. https://doi.org/10.1016/j.vaccine.2018.02.111 Molano I, Alonso MG, Mirón C, Redondo E, Requena JM, Soto M, Nieto CG, Alonso C. A Leishmania infantum multi-component antigenic protein mixed with live BCG confers protection to dogs experimentally infected with L. infantum . Vet Immunol Immunopathol. 2003;92:1–13. https://doi.org/10.1016/S0165-2427(02)00315-X Carcelén J, Iniesta V, Fernández-Cotrina J, Serrano F, Parejo JC, Corraliza I, Gallardo-Soler A, Marañón F, Soto M, Alonso C, Gómez-Nieto C. The chimerical multi-component Q protein from Leishmania in the absence of adjuvant protects dogs against an experimental Leishmania infantum infection. Vaccine. 2009; 27:5964–73. https://doi.org/10.1016/j.vaccine.2009.07.069 Fernández Cotrina J, Iniesta V, Monroy I, Baz V, Hugnet C, Marañon F, Fabra M, Gómez-Nieto LC, Alonso C. A large-scale field randomized trial demonstrates safety and efficacy of the vaccine LetiFend® against canine leishmaniosis. Vaccine. 2018; 36:1972–1982. https://doi.org/10.1016/j.vaccine.2018.02.111 European Medicines Agency. LetiFend®: Summary of Product Characteristics. https://www.ema.europa.eu/en/medicines/veterinary/EPAR/letifend Leite JC, Gonçalves AAM, de Oliveira DS, Resende LA, Boas DFV, Ribeiro HS, Pereira DFS, da Silva AV, Mariano RMDS, Reis PCC, Nakasone EN, França-Silva JC, Galdino AS, Paes PRO, Melo MM, Dias ES, Chávez-Fumagalli MA, da Silveira-Lemos D, Dutra WO, Giunchetti RC. Transmission-Blocking Vaccines for Canine Visceral Leishmaniasis: New Progress and Yet New Challenges. Vaccines (Basel). 2023; 11:1565. https://doi.org/10.3390/vaccines11101565 Reis AB, Giunchetti RC, Carrillo E, Martins-Filho OA, Moreno J. Immunity to Leishmania and the rational search for vaccines against canine leishmaniasis. Trends Parasitol. 2010; 26:341–9. https://doi.org/10.1016/j.pt.2010.04.005 Fernández Cotrina J, Iniesta V, Monroy I, Baz V, Hugnet C, Marañon F, Fabra M, Gómez-Nieto LC, Alonso C. A large-scale field randomized trial demonstrates safety and efficacy of the vaccine LetiFend® against canine leishmaniosis. Vaccine. 2018; 36:1972–1982. https://doi.org/10.1016/j.vaccine.2018.02.111 Regulation (EU) 2019/6 of the European Parliament and of the Council of 11 December 2018 on veterinary medicinal products and repealing Directive 2001/82/EC https://eur-lex.europa.eu/eli/reg/2019/6/oj and/or https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32019R0006 Toepp A, Larson M, Grinnage-Pulley T, Bennett C, Anderson M, Parrish M, Fowler H, Wilson G, Gibson-Corely K, Gharpure R, Cotter C, Petersen C. Safety Analysis of Leishmania Vaccine Used in a Randomized Canine Vaccine/Immunotherapy Trial. Am J Trop Med Hyg. 2018; 98:1332–1338. https://doi.org/10.4269/ajtmh.17-0888 Cacheiro-Llaguno C, Parody N, Renshaw-Calderón A, Osuna C, Alonso C, Carnés J. Vaccination with LetiFend® reduces circulating immune complexes in dogs experimentally infected with L. infantum . Vaccine. 2020; 38:890–896. https://doi.org/10.1016/j.vaccine.2019.10.078 Miles SA, Conrad SM, Alves RG, Jeronimo SM, Mosser DM. A role for IgG immune complexes during infection with the intracellular pathogen Leishmania . J Exp Med. 2005; 201: 747–54. https://doi.org/10.1084/jem.20041470 Schäfer I, Müller E, Naucke TJ. Ein update zur leishmaniose des hundes: diagnostik, therapie und monitoring. Tierarztl Prax Ausg K Klientiere Heimtiere 2022; 50(6): 431–445. http://doi.org/10.1055/a-1970-9590 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7886906","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Short Report","associatedPublications":[],"authors":[{"id":531958538,"identity":"f5023c31-2ccb-4f8a-9946-458880bf8034","order_by":0,"name":"Tobias Werner","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA70lEQVRIiWNgGAWjYDADfgkow4CBsYGBgQ23Sh4YQ3IGyVoMbsC1gAAeLfYMPIaPK3fY5Bvfbn/AdKPmTp45e3PrBoYyGzy28Bgbnj2TZrntzhkD5pxjz4otew623WA4l4ZHC+82yca2wwZmN3LYf+ewHU7ccCOx7QZj22F8Wrb/bGz7b2A8I/0Bc84/oJb7D0Fa/uO1hbGx7YCBgUSCAXNuG8gWRpCWA7i1HOb/DHRYsoHEjRyglj6gljNAhyWcS8aphb29LfFjY5udAT/YYd+AWo4ff3bjQ5kdTi0MzFhFE3BrGAWjYBSMglFABAAAAbZYMlC/dAoAAAAASUVORK5CYII=","orcid":"","institution":"Mannheim Technical University of Applied Sciences","correspondingAuthor":true,"prefix":"","firstName":"Tobias","middleName":"","lastName":"Werner","suffix":""},{"id":531958539,"identity":"15d6b26b-20e4-4caf-9184-8e9691dfc3fe","order_by":1,"name":"Marius Rămneanţu","email":"","orcid":"","institution":"Small Animal Clinic D.V.M.s","correspondingAuthor":false,"prefix":"","firstName":"Marius","middleName":"","lastName":"Rămneanţu","suffix":""},{"id":531958540,"identity":"d978e787-959a-47e4-bc6f-04d1719311d3","order_by":2,"name":"Torsten J. 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13:57:12","extension":"html","order_by":10,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":129361,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7886906/v1/ad513b939e900c0bd337e5bc.html"},{"id":94396409,"identity":"09e6f564-0350-4912-a136-f5c41ca61f4a","added_by":"auto","created_at":"2025-10-27 13:55:58","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":515121,"visible":true,"origin":"","legend":"\u003cp\u003eA ca. 3-year-old male mixed breed dog found in the Sardinian outback \u003cbr\u003e\ninfested with at least 15 ticks of the species \u003cem\u003eR. sanguineus\u003c/em\u003e.\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7886906/v1/95208b31547cb8eb385a76b5.jpeg"},{"id":94399002,"identity":"0607401a-5ddd-49d2-9b40-b3d4e0b9da0c","added_by":"auto","created_at":"2025-10-27 13:57:19","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":80584,"visible":true,"origin":"","legend":"\u003cp\u003eChanges in serum protein capillary electrophoresis over time after administration of a single dose of Letifend® indicating a significant drop of the production of non-protective IGG and thus a reduction in the formation of \u003cbr\u003e\ncirculating immune complexes over time.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-7886906/v1/5b8ae886f5de920108550706.png"},{"id":94398650,"identity":"f05cbe4f-09f2-4873-8508-9e5e89e64ee6","added_by":"auto","created_at":"2025-10-27 13:57:10","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":429916,"visible":true,"origin":"","legend":"\u003cp\u003eThree weeks after therapeutic vaccination with Letifend®, the dog had almost fully recovered and showed normal activity, and has remained healthy for over three years.\u003c/p\u003e","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7886906/v1/69eb3605fa88f351a0a63bbf.jpeg"},{"id":99315641,"identity":"62b6f748-83a8-4a91-8cf3-a092c1cdb2fa","added_by":"auto","created_at":"2025-12-31 16:27:10","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1570768,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7886906/v1/440c5cf1-6559-4f90-9c91-e72202f6f155.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Therapeutic vaccination reverses severe canine leishmaniasis: a case report","fulltext":[{"header":"Main text","content":"\u003cp\u003eCanine leishmaniasis (CanL), caused by \u003cem\u003eLeishmania infantum\u003c/em\u003e, poses ongoing therapeutic challenges in veterinary medicine, particularly in endemic regions such as Southern Europe, South America, and parts of Asia [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. The disease is transmitted by phlebotomine sandflies and manifests as a systemic infection that can lead to severe, life-threatening conditions if left untreated. CanL is characterized by its complex pathophysiology, chronic progression, and high relapse rates, making treatment particularly difficult.\u003c/p\u003e\u003cp\u003eTherapeutic strategies for CanL differ substantially between endemic and non-endemic areas. In endemic regions, such as Southern Europe, South America, and parts of Asia, the preferred therapy involves the use of leishmanicidal drugs. These include antimonial drugs, such as meglumine antimoniate and miltefosine, an alkylphosphocholine originally developed as an antineoplastic agent. Both exhibit significant antileishmanial activity and are the preferred drugs in all Mediterranean countries for the treatment of CanL, as a rule administered in combination with the leishmaniostatic drug allopurinol, a purine analogue that inhibits parasite replication. Leishmanicidal drugs aim to reduce the parasite load and manage the disease more aggressively. This approach is essential to decrease the amastigote load in the dog, thereby reducing the risk of transmission to other animals and humans [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. However, these treatments are frequently associated with severe side effects, including nephrotoxicity, hepatotoxicity, pancreatitis and gastrointestinal distress [4\u0026ndash;7]. Moreover, increasing reports of drug resistance in \u003cem\u003eLeishmania infantum\u003c/em\u003e have raised concerns about the long-term efficacy of treatments using meglumine antimoniate or miltefosine [\u003cspan additionalcitationids=\"CR9\" citationid=\"CR7\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIn non-endemic areas, the emphasis is on using leishmaniostatic drugs, particularly when typical clinical manifestations are absent. Allopurinol is commonly used as a first-line treatment in these regions due to its ability to inhibit parasite replication without the same level of toxicity associated with leishmanicidal drugs. Allopurinol aims to maintain a balance between controlling the infection and minimizing adverse effects, especially given the lower risk of reinfection in non-endemic areas. However, long-term administration may also be problematic here, as there is a risk of developing xanthine urolithiasis [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e12\u003c/span\u003e] and contribute to drug resistance [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eAlternative treatments may include herbal remedies, such as chamomile (\u003cem\u003eMatricaria chamomilla\u003c/em\u003e) and artemisinin, which have shown antileishmanial properties. Artemisinin, a sesquiterpene lactone primarily used in malaria treatment, has shown potential in reducing parasite loads in experimental settings [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Similarly, α-bisabolol, a natural monocyclic sesquiterpene alcohol found in chamomile has been identified as a potent inhibitor of \u003cem\u003eLeishmania\u003c/em\u003e promastigotes and amastigotes [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. While these alternative treatments demonstrate preclinical efficacy, they require further clinical validation before they can be widely adopted as part of standard CanL treatment protocols.\u003c/p\u003e\u003cp\u003eGiven the limitations of conventional drug therapies, immunomodulatory approaches have gained increasing attention in CanL management. Rather than targeting the parasite directly, these treatments aim to enhance the host's immune response to control infection and prevent disease progression.\u003c/p\u003e\u003cp\u003eOne of the most well-known immunomodulators in veterinary medicine is domperidone, a dopamine D₂ receptor antagonist that stimulates prolactin secretion, which in turn modulates cell-mediated immunity. Prolactin enhances macrophage activation and promotes the Th1 immune response, which is critical for controlling Leishmania infections. Studies have shown that domperidone can reduce the severity of clinical signs in infected dogs and may help prevent disease progression [\u003cspan additionalcitationids=\"CR18 CR19\" citationid=\"CR16\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. However, it is most effective in early-stage infections or as a prophylactic measure in dogs at high risk of exposure.\u003c/p\u003e\u003cp\u003eAnother promising immunomodulator is impromune, a nutraceutical formulation that contains Nucleoforce\u0026reg; (nucleotide-based immunostimulant) and AHCC\u0026reg; (active hexose correlated compound, derived from mushrooms). These components enhance the function of NK cells and macrophages, leading to an improved Th1 immune response. Clinical studies have suggested that impromune can help maintain immune homeostasis and support the recovery of infected dogs, particularly when used in combination with antiparasitic drugs [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eWhile vaccination has traditionally been used as a prophylactic measure, recent studies suggest that it may also possess therapeutic potential in CanL management [\u003cspan additionalcitationids=\"CR24 CR25\" citationid=\"CR22\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Several vaccines [27,28] have been developed to induce protective immunity against \u003cem\u003eL. infantum\u003c/em\u003e, with Letifend\u0026reg; being one of the most promising candidates [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eLetifend\u0026reg; is a recombinant protein-based vaccine that contains Q protein as active ingredient, that stimulates the Th1 immune response resulting in a long-lasting cellular and humoral response and activation in macrophages to produce nitric oxide radicals which are crucial for controlling \u003cem\u003eLeishmania\u003c/em\u003e infections [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. After experimental infection, Letifend\u0026reg;-vaccinated dogs showed a lower intensity of clinical symptoms [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. The vaccine demonstrated 72% efficacy (95% CI: 65\u0026ndash;79%) in preventing clinical CanL in controlled trials [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e32\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThus, the vaccine was granted a marketing authorization for valid throughout the European Union in 2016 [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e33\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. Generally, Letifend\u0026reg; is indicated for the immunization of non-infected dogs from six months of age to reduce the risk of developing an active infection and/or clinical disease after exposure to \u003cem\u003eL. infantum\u003c/em\u003e [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. In addition to its role in disease prevention, there is emerging evidence that therapeutic vaccination with Letifend\u0026reg; may enhance the immune response in already infected dogs, potentially leading to clinical improvement.\u003c/p\u003e"},{"header":"The case","content":"\u003cp\u003eIn this case report, we present a dog suffering from severe, life-threatening CanL that exhibited an unexpectedly rapid clinical recovery following a single-dose vaccination with Letifend\u0026reg;. Over the course of a few weeks, the dog's clinical condition improved dramatically, and laboratory parameters normalized, indicating a potential immunotherapeutic effect of the vaccine.\u003c/p\u003e\u003cp\u003eOur findings suggest that vaccination with Letifend\u0026reg; could represent a novel therapeutic strategy for CanL, particularly in cases where conventional therapies are ineffective or associated with severe side effects. These results highlight the need for further clinical studies to explore the immunomodulatory effects of vaccination in CanL treatment. If confirmed in larger cohorts, therapeutic vaccination could revolutionize CanL management, offering a safer and more effective alternative to traditional drug-based therapies.\u003c/p\u003e\u003cp\u003eIn Summer 2021, a male mixed-breed dog, approximately three years old, was found in a critical condition near a roadside in a remote part of Sardinia. The dog was very lethargic, strongly dehydrated and severely anemic, displaying extreme weakness and pale mucous membranes. Upon closer examination, the dog was found to be infested with at least 15 ticks of the species \u003cem\u003eR. sanguineus\u003c/em\u003e. The presence of this tick species raised immediate concern for vector-borne infections, as \u003cem\u003eR. sanguineus\u003c/em\u003e is a known carrier of multiple hemopathogens.\u003c/p\u003e\u003cp\u003eUpon arrival in an animal shelter, the dog received supportive care, including fluid therapy, hematinic supplements, and antimicrobial treatment with doxycycline (10 mg/kg, PO, SID for 28 days). The decision to administer doxycycline was driven by its broad-spectrum efficacy against \u003cem\u003eEhrlichia spp., Anaplasma spp\u003c/em\u003e., and other bacterial pathogens commonly transmitted by \u003cem\u003eR. sanguineus\u003c/em\u003e, with its effectiveness being highest during the acute phase of infection.\u003c/p\u003e\u003cp\u003eOver the following weeks, the dog gradually recovered, showing significant clinical improvement. Follow-up hematological tests revealed stabilized erythrocyte levels within the normal range, and the dog regained weight and strength. However, systematic screening for vector-borne diseases was omitted at the time.\u003c/p\u003e\u003cp\u003eSeveral months later, the dog developed signs of urinary discomfort, leading to further diagnostics. A large struvite-type bladder stone was identified via ultrasound and subsequently removed. Following this intervention, the dog remained clinically stable. However, due to the lack of systematic screening for vector-borne infections at initial presentation, potential chronic infections such as subclinical ehrlichiosis or leishmaniasis, could not be ruled out.\u003c/p\u003e\u003cp\u003eIn April 2022 a family was found for the dog and it was transferred to Germany. Due to the above-mentioned history, it underwent a thorough veterinary examination to check for infectious diseases common in the Mediterranean region. Clinical laboratory parameters were evaluated.\u003c/p\u003e\u003cp\u003eThe following analytical methods were applied to the blood and urine samples.\u003c/p\u003e\u003cp\u003eBlood Cell Analysis: Complete blood counts were determined using EDTA-anticoagulated whole blood samples analyzed with the scil Vet abc Plus\u0026thinsp;+\u0026thinsp;automated hematology analyzer (scil Animal Care Company, Viernheim, Germany). This fully automated system employs impedance technology and flow cytometry to quantify erythrocyte, leukocyte, and platelet parameters.\u003c/p\u003e\u003cp\u003eSerum Capillary Electrophoresis: Serum protein electrophoresis was performed using the MINICAP FLEX-PIERCING system (Sebia, Lisses, France). This capillary electrophoresis technique separates serum proteins into six fractions (albumin, α1-, α2-, β1-, β2- and γ-globulins) based on their electrophoretic mobility under alkaline conditions. Urinalysis was performed using IDEXX UA test strips and the IDEXX VetLab UA point-of-care urine chemistry analyser (IDEXX Laboratories, Westbrook, ME, USA)\u003c/p\u003e\u003cp\u003eImmunofluorescence Antibody Test (IFAT): Anti-\u003cem\u003eLeishmania infantum\u003c/em\u003e antibody titers were determined using a semi-quantitative IFAT MegaFLUO\u0026reg; LEISH Kit (MEGACOR Diagnostik GmbH, H\u0026ouml;rbranz, Austria). Serum samples were serially diluted (1:50, 1:100, 1:200, 1:500, 1:1000, 1:2000, 1:4000, and 1:8000) and applied to slides pre-coated with \u003cem\u003eL. infantum\u003c/em\u003e promastigotes. After 30 minutes of incubation at room temperature, the slides were washed (5 minutes with phosphate-buffered saline) and treated with fluorescein-labeled conjugate (30 minutes, in the dark). Following a final wash, the slides were mounted and examined under a Nikon Eclipse 80i fluorescence microscope equipped with an FITC filter set (excitation: 465\u0026ndash;495 nm, dichroic mirror: 505 nm, emission: 515\u0026ndash;555 nm) and a 100 W mercury vapor lamp (Osram HBO 103 W/2) at 400\u0026times; magnification. Positive samples showed distinct yellow-green fluorescence on the cytoplasmic membrane at a cut-off dilution of 1:100. Negative samples exhibited either gray coloration without fluorescence or aberrant fluorescence patterns. Fluorescence on the flagella of promastigotes was also assessed as negative.\u003c/p\u003e\u003cp\u003eThe dog was tested positive for \u003cem\u003eL. infantum\u003c/em\u003e with a titer of 1:4000. Hematology showed lymphopenia, anemia, and thrombocytopenia (see Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Allopurinol (2 x 5 mg/kg BID) was initiated, but the dog deteriorated markedly, developing anorexia, diarrhea, and worsening anemia. Unfortunately, the dog's general condition deteriorated markedly over the following weeks. It stopped eating and drinking voluntarily, developed diarrhea, and experienced a further increase in anemia, indicated by pale mucous membranes. The dog became very apathetic and lethargic, only leaving its resting place to vomit.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eLaboratory parameters recorded at time 0 (T0) and after 6 (T6), 12 (T12), and 24 (T24) month after diagnosis\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"11\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSubstrate\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eParameter\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003eT0\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u003cp\u003eT6\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e\u003cp\u003eT12\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e\u003cp\u003eT24\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c11\"\u003e\u003cp\u003eNormal range\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSerum*\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTotal protein (g/L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003e83.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u003cp\u003e67.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e\u003cp\u003e67.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e\u003cp\u003e79.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e54.0\u0026ndash;75.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAlb/Glob ratio\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003e0.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u003cp\u003e1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e\u003cp\u003e1.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e\u003cp\u003e1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e\u0026gt;\u0026thinsp;0.6\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eGamma globulin (g/L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e24.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"4\" rowspan=\"5\"\u003e\u003cp\u003e59.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e12.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\" morerows=\"4\" rowspan=\"5\"\u003e\u003cp\u003e30.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e12.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\" morerows=\"4\" rowspan=\"5\"\u003e\u003cp\u003e33.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e16.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\" morerows=\"4\" rowspan=\"5\"\u003e\u003cp\u003e41.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\" morerows=\"4\" rowspan=\"5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;45\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBeta 2 globulin (g/L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e13.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e6.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e6.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e8.7\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBeta 1 globuloin (g/L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e13.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e4.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e4.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e7.7\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAlpha 2 globulin (g/L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e4.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e5.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e5.3\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAlpha 1 globulin (g/L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e3.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e3.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e3.7\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAlbumin (g/L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003e23.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u003cp\u003e34.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e\u003cp\u003e34.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e\u003cp\u003e37.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e25.0\u0026ndash;44.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eIFAT-titer Leishmania\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003e1:4000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u003cp\u003e1:1000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e\u003cp\u003e1:2000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e\u003cp\u003e1:4000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003enegative\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBlood\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eWBC (10\u003csup\u003e3\u003c/sup\u003e/\u0026micro;L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003e4.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u003cp\u003e9.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e\u003cp\u003e8.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e\u003cp\u003e6.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e6.0\u0026ndash;12.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eRBC (10\u003csup\u003e6\u003c/sup\u003e/mL)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003e3.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u003cp\u003e5.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e\u003cp\u003e6.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e\u003cp\u003e6.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e5.5\u0026ndash;8.5\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHB (g/dL)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003e8.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u003cp\u003e15.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e\u003cp\u003e15.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e\u003cp\u003e15.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e15.0\u0026ndash;20.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHcT (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003e25.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u003cp\u003e44.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e\u003cp\u003e44.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e\u003cp\u003e45.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e44.0\u0026ndash;57.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePLT (K/\u0026micro;L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003e98.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u003cp\u003e237\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e\u003cp\u003e202\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e\u003cp\u003e229\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e200\u0026ndash;460\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eUrin\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eEry (Ery/\u0026micro;L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u003cp\u003enegative\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e\u003cp\u003enegative\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e\u003cp\u003enegative\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003enegative\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eProtein (mg/L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003e250\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u003cp\u003enegative\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e\u003cp\u003enegative\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e\u003cp\u003enegative\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003enegative\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"11\"\u003e* All measured serum concentrations of creatinine and urea remained within the normal range throughout the entire period.\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eDue to potential side effects of typical leishmanicidal drugs, it was decided that it should not receive classic therapy with leishmanicidal medication due to its serious state of health. Instead, the dog was administered a single dose of Letifend\u0026reg; with the intention of giving it the fastest and most effective immune response possible to combat the pathogen. According to the \u0026ldquo;veterinary medicinal products regulation\u0026rdquo; this alternative treatment option, the so-called \u0026ldquo;cascade system\u0026rdquo;, permitting off-label use when standard therapies fail or is considered to be non-effective [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. In fact, the decision did not pose a major concern as the manufacturer did not consider there to be any risk to infected dogs. Rather, it is stated that the vaccine can be used safely in infected dogs. Also, booster vaccination of infected dogs did not worsen the course of the disease [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e38\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e39\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eAt this point in time, the dog was fed a watery mash of its favorite food. After just 10 days, its general condition improved, and within three weeks, it showed almost normal activity. Exercise tolerance normalized, allowing unrestricted activity (\u0026gt;\u0026thinsp;3 km/day).\u003c/p\u003e\u003cp\u003eThe laboratory values presented in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e demonstrate that immunomodulation with Letifend\u0026reg; produced a sustained effect. Notably, the rising albumin/globulin ratio clearly indicates a swift and effective shift to a cellular Th1 immune response, efficiently countering the pathogens. Subsequently, the course of the health status and of the laboratory values were monitored over a period of 2 years. The serum protein capillary electrophoreses in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e show a gradual lowering of the gamma-fraction over time, indicating a decrease of the non-protective IgG, that can substantially contribute to disease progression through the formation of pathogenic immune complexes by the respective IgG with circulating antigens [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. During this period, no further therapeutic actions were taken to treat the leishmaniasis.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eOnly two years after the Letifend\u0026reg; administration, the laboratory parameters showed mild deterioration and an allopurinol / domperidone therapy was started, which has been successfully continued to the present day, according to a staged protocol, as recommended for non-endemic areas.\" [\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e41\u003c/span\u003e]. The dog is still clinically healthy with regard to the \u003cem\u003eL. infantum\u003c/em\u003e infection.\u003c/p\u003e\u003cp\u003eThis case highlights the complexity of diagnosing and managing vector-borne diseases in rescued dogs, particularly those originating from endemic regions such as Sardinia. The absence of systematic serological or molecular screening at the time of rescue resulted in an undiagnosed chronic \u003cem\u003eL. infantum\u003c/em\u003e underscores the necessity of comprehensive diagnostic protocols for rescued dogs, even in the absence of overt clinical symptoms at the time of admission. The dog\u0026rsquo;s rapid deterioration following its relocation to Germany revealed the progressive nature of untreated leishmaniasis. Despite the initiation of standard allopurinol therapy, the dog's condition continued to decline, necessitating an alternative approach. The therapeutic administration of a single dose of the Letifend\u0026reg; vaccine resulted in a remarkably rapid and sustained clinical improvement, with stabilized laboratory parameters and a marked shift towards a protective Th1 immune response.\u003c/p\u003e\u003cp\u003eThe case suggests that therapeutic vaccination with Letifend\u0026reg; may play a crucial role in modulating immune responses in dogs with clinical leishmaniasis, potentially offering an alternative or complementary approach to conventional treatments. The observed long-term immunomodulatory effect further supports the hypothesis that vaccination could enhance host immune control of \u003cem\u003eL. infantum\u003c/em\u003e infections. It must be assumed that the effectiveness of the therapeutic use of Letifend\u0026reg; depends on a number of factors, such as genetics, breed, immune status and phase of the disease, that are still relatively unknown. Therefore, the use of Letifend\u0026reg; is currently not a generally applicable alternative for the treatment of leishmaniasis, but in individual cases it can actually be life-saving. Attention must also be paid to the fact that mild deterioration of laboratory values two years post-vaccination emphasizes the need for long-term monitoring and, in some cases, the reintroduction of adjunctive therapies such as allopurinol and domperidone to maintain disease control. This case highlights the promising potential of Letifend\u0026reg; as a therapeutic option, suggesting that further research is needed to understand its role in managing CanL, especially in dogs with established infections where conventional treatments might fall short. The evidence supports the need for more investigation into its effectiveness in such cases.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eAlb\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eAlbumin\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eCanL\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eCanine leishmaniasis\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eEDTA\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eEthylenediaminetetraacetic acid\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eEry\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eErythrocytes\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eFITC\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eFluorescein isothiocyanate\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eGlob\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eGlobulin\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eHb\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eHemoglobin\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eHcT\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eHematocrit\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eIFAT\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eImmunofluorescence antibody test\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eIgG\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eImmunoglobulin G\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eNK\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eNatural killer\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003ePLT\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ePlatelet count\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eRBC\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eRed blood cell count\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eTh1\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eT helper 1 cells\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eWBC\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eWhite blood cell count\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eRBC\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eRed blood cell count\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003ch2\u003eEthics approval and consent to participate\u003c/h2\u003e\u003cp\u003eNo ethical approval was required.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003cp\u003eNot applicable.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003ch2\u003eAuthor details (optional)\u003c/h2\u003e\u003cp\u003eMR: [email protected]\u003c/p\u003e\u003cp\u003eTN: [email protected]\u003c/p\u003e\u003cp\u003eTW: [email protected]\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e\u003cp\u003eThis research received no specific grant from any funding agency in the public, commercial, or not for profit sectors.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eThe dog featured in this report, owned by TW, was under the care of MR, who performed all clinical examinations and treatments. All procedures were conducted in consultation and agreement with all authors. Laboratory analyses were carried out by TN and MR, with TN specifically responsible for the microscopic examination and serum electrophoresis. TW wrote the manuscript, and all authors reviewed, read, and approved the final version.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eWe thank the employees of the animal shelter \"I Fratelli Minori\" of the non-profit organization LIDA in Olbia (Italy) for providing all the information about the dog in the study.\u003c/p\u003e\u003ch2\u003eAvailability of data and materials\u003c/h2\u003e\u003cp\u003eAll available data generated during this study are included in the published article.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003ePriolo V, Ippolito D, Rivas-Estanga K, De Waure C, Mart\u0026iacute;nez-Orellana P. Canine leishmaniosis global prevalence over the last three decades: a meta-analysis and systematic review. Comparative Immunology, Microbiology and Infectious Diseases. 2024; 112:102211. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.tvjl.2006.10.019\u003c/span\u003e\u003cspan address=\"10.1016/j.tvjl.2006.10.019\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMorales-Yuste M, Mart\u0026iacute;n-S\u0026aacute;nchez J, Corpas-Lopez V. Canine leishmaniasis: Update on epidemiology, diagnosis, treatment, and prevention. Veterinary Sciences. 2022; 9(8):387. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/vetsci9080387\u003c/span\u003e\u003cspan address=\"10.3390/vetsci9080387\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSolano-Gallego L, Mir\u0026oacute; G, Koutinas A, Cardoso L, Pennisi MG, Ferrer L, Bourdeau P, Oliva G, Baneth G, The LeishVet Group. LeishVet guidelines for the practical management of canine leishmaniosis. Parasit Vectors. 2011; 4:86. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1186/1756-3305-4-86\u003c/span\u003e\u003cspan address=\"10.1186/1756-3305-4-86\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWoerly V, Maynard L, Sanquer A, Eun HM. Clinical efficacy and tolerance of miltefosine in the treatment of canine leishmaniosis. Parasitol Res. 2009; 105:463\u0026ndash;9. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s00436-009-1404-2\u003c/span\u003e\u003cspan address=\"10.1007/s00436-009-1404-2\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMateo M, Maynard L, Vischer C, Bianciardi P, Mir\u0026oacute; G. Comparative study on the short term efficacy and adverse effects of miltefosine and meglumine antimoniate in dogs with natural leishmaniosis. Parasitol Res. 2009; 105:155\u0026ndash;62. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s00436-009-1375-3\u003c/span\u003e\u003cspan address=\"10.1007/s00436-009-1375-3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMoritz A, Steuber S, Greiner M. Clinical follow-up examination after treatment of canine leishmaniasis. Tokai J Exp Clin Med. 1998; 23:279\u0026thinsp;\u0026ndash;\u0026thinsp;83. [7] Vi\u0026ntilde;eta C, Castro J, L\u0026oacute;pez MC, Frau M, Costas A, Arenas C, Roura X. Is pancreatitis associated with meglumine antimoniate treatment for canine leishmaniosis? A multicentric prospective study. Parasit Vectors. 2024; 17:532. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1186/s13071-024-06617-7\u003c/span\u003e\u003cspan address=\"10.1186/s13071-024-06617-7\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGizzarelli M, Foglia Manzillo V, Inglese A, Montagnaro S, Oliva G. Retrospective Long-Term Evaluation of Miltefosine-Allopurinol Treatment in Canine Leishmaniosis. Pathogens. 2023; 12:864. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/pathogens12070864\u003c/span\u003e\u003cspan address=\"10.3390/pathogens12070864\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eAshutosh, Sundar S, Goyal N. Molecular mechanisms of antimony resistance in \u003cem\u003eLeishmania\u003c/em\u003e. J Med Microbiol. 2007; 56:143\u0026thinsp;\u0026ndash;\u0026thinsp;53. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1099/jmm.0.46841-0\u003c/span\u003e\u003cspan address=\"10.1099/jmm.0.46841-0\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMoncada-Diaz MJ, Rodr\u0026iacute;guez-Almonacid CC, Quiceno-Giraldo E, Khuong FTH, Muskus C, Karamysheva ZN. Molecular Mechanisms of Drug Resistance in \u003cem\u003eLeishmania\u003c/em\u003e spp. Pathogens. 2024; 27;13:835. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/pathogens13100835\u003c/span\u003e\u003cspan address=\"10.3390/pathogens13100835\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eJesus L, Arenas C, Dom\u0026iacute;nguez-Ruiz M, Silvestrini P, Englar RE, Roura X, Leal RO. Xanthinuria secondary to allopurinol treatment in dogs with leishmaniosis: Current perspectives of the Iberian veterinary community. Comp Immunol Microbiol Infect Dis. 2022; 83:101783. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.cimid.2022.101783\u003c/span\u003e\u003cspan address=\"10.1016/j.cimid.2022.101783\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eTorres M, Bardag\u0026iacute; M, Roura X, Zanna G, Ravera I, Ferrer L. Long term follow-up of dogs diagnosed with leishmaniosis (clinical stage II) and treated with meglumine antimoniate and allopurinol. Vet J. 2011;188:346\u0026ndash;51. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.tvjl.2010.05.025\u003c/span\u003e\u003cspan address=\"10.1016/j.tvjl.2010.05.025\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eYasur-Landau D, Jaffe CL, Doron-Faigenboim A, David L, Baneth G. Induction of allopurinol resistance in \u003cem\u003eLeishmania infantum\u003c/em\u003e isolated from dogs. PLoS Negl Trop Dis. 2017;11:e0005910. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1371/journal.pntd.0005910\u003c/span\u003e\u003cspan address=\"10.1371/journal.pntd.0005910\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSch\u0026auml;fer I, Faucher M, Nachum-Biala Y, Ferrer L, Carrasco M, Kehl A, M\u0026uuml;ller E, Naucke TJ, Baneth G. Evidence for in vivo resistance against allopurinol in a dog infected with \u003cem\u003eLeishmania infantum\u003c/em\u003e by reduction in copy numbers of the S-adenosylmethionine synthetase (METK) gene. Parasit Vectors. 2024; 17:506. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1186/s13071-024-06583-0\u003c/span\u003e\u003cspan address=\"10.1186/s13071-024-06583-0\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMedkour H, Bitam I, Laidoudi Y, Lafri I, Lounas A, Hamidat HK, Mekroud A, Varloud M, Davoust B, Mediannikov O. Potential of Artesunate in the treatment of visceral leishmaniasis in dogs naturally infected by \u003cem\u003eLeishmania infantum\u003c/em\u003e: Efficacy evidence from a randomized field trial. PLoS Negl Trop Dis. 2020;14:e0008947. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1371/journal.pntd.0008947\u003c/span\u003e\u003cspan address=\"10.1371/journal.pntd.0008947\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCorpas-L\u0026oacute;pez V, Merino-Espinosa G, Acedo-S\u0026aacute;nchez C, D\u0026iacute;az-S\u0026aacute;ez V, Navarro-Moll MC, Morillas-M\u0026aacute;rquez F, Mart\u0026iacute;n-S\u0026aacute;nchez J. Effectiveness of the sesquiterpene (-)-α-bisabolol in dogs with naturally acquired canine leishmaniosis: an exploratory clinical trial. Vet Res Commun. 2018; 42:121\u0026ndash;130. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s11259-018-9714-4\u003c/span\u003e\u003cspan address=\"10.1007/s11259-018-9714-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCavalera MA, Gernone F, Uva A, D'Ippolito P, Roura X, Paltrinieri S, Zatelli A. Effect of domperidone (leisguard\u0026reg;) on antibody titers, inflammatory markers and creatinine in dogs with leishmaniosis and chronic kidney disease. Parasit Vectors. 2021; 14:525. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1186/s13071-021-05030-8\u003c/span\u003e\u003cspan address=\"10.1186/s13071-021-05030-8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCavalera MA, Gernone F, Uva A, Donghia R, Zizzadoro C, Zatelli A. Efficacy of domperidone plus renal diet in slowing the progression of chronic kidney disease in dogs with leishmaniosis. Parasit Vectors. 2022; 15:397. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1186/s13071-022-05537-8\u003c/span\u003e\u003cspan address=\"10.1186/s13071-022-05537-8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSabat\u0026eacute; D, Llin\u0026aacute;s J, Homedes J, Sust M, Ferrer L. A single-centre, open-label, controlled, randomized clinical trial to assess the preventive efficacy of a domperidone-based treatment programme against clinical canine leishmaniasis in a high prevalence area. Prev Vet Med. 2014; 115:56\u0026ndash;63. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.prevetmed.2014.03.010\u003c/span\u003e\u003cspan address=\"10.1016/j.prevetmed.2014.03.010\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBaxarias M, Donato G, Mateu C, Salichs M, Homedes J, Mir\u0026oacute; G, Pennisi MG, Solano-Gallego L. A blinded, randomized and controlled multicenter clinical trial to assess the efficacy and safety of Leisguard\u0026reg; as an immunotherapeutic treatment for healthy \u003cem\u003eLeishmania infantum\u003c/em\u003e-seropositive dogs. Parasit Vectors. 2023; 16:344. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1186/s13071-023-05903-0\u003c/span\u003e\u003cspan address=\"10.1186/s13071-023-05903-0\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSegarra S, Mir\u0026oacute; G, Montoya A, Pardo-Mar\u0026iacute;n L, Teichenn\u0026eacute; J, Ferrer L, Cer\u0026oacute;n JJ. Prevention of disease progression in \u003cem\u003eLeishmania infantum\u003c/em\u003e-infected dogs with dietary nucleotides and active hexose correlated compound. Parasit Vectors. 2018; 11:103. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1186/s13071-018-2705-z\u003c/span\u003e\u003cspan address=\"10.1186/s13071-018-2705-z\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMir\u0026oacute; G, Segarra S, Cer\u0026oacute;n JJ, Ferrer L, Solano-Gallego L, Montell L, Costa E, Teichenne J, Marin\u0026eacute;-Casad\u0026oacute; R; GALILEI trial Group; Roura X. New immunomodulatory treatment protocol for canine leishmaniosis reduces parasitemia and proteinuria. PLoS Negl Trop Dis. 2024; 18:e0012712. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1371/journal.pntd.0012712\u003c/span\u003e\u003cspan address=\"10.1371/journal.pntd.0012712\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eRoatt BM, Aguiar-Soares RD, Reis LE, Cardoso JM, Mathias FA, de Brito RC, da Silva SM, Gontijo NF, Ferreira SA, Valenzuela JG, Corr\u0026ecirc;a-Oliveira R, Giunchetti RC, Reis AB. A Vaccine Therapy for Canine Visceral Leishmaniasis Promoted Significant Improvement of Clinical and Immune Status with Reduction in Parasite Burden. Front Immunol. 2017;8:217. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3389/fimmu.2017.00217\u003c/span\u003e\u003cspan address=\"10.3389/fimmu.2017.00217\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCoelho, E.A.F., Christodoulides, M. (2023). Vaccines for Canine Leishmaniasis. In: Christodoulides, M. (eds) Vaccines for Neglected Pathogens: Strategies, Achievements and Challenges. Springer, Cham. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/978-3-031-24355-4_13\u003c/span\u003e\u003cspan address=\"10.1007/978-3-031-24355-4_13\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eElsheikha, Hany. \"Leishmaniosis in canines: part 1\u0026ndash;treating and controlling infection.\" 2016: 20163118985. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.vettimes.co.uk/app/uploads/wp-post-to-pdf-enhanced-cache/1/leishmaniosis-in-canines-part-1-treating-and-controlling-infection.pdf\u003c/span\u003e\u003cspan address=\"https://www.vettimes.co.uk/app/uploads/wp-post-to-pdf-enhanced-cache/1/leishmaniosis-in-canines-part-1-treating-and-controlling-infection.pdf\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eNascimento LFM, Miranda DFH, Moura LD, Pinho FA, Werneck GL, Khouri R, Reed SG, Duthie MS, Barral A, Barral-Netto M, Cruz MSP. Allopurinol therapy provides long term clinical improvement, but additional immunotherapy is required for sustained parasite clearance, in \u003cem\u003eL. infantum\u003c/em\u003e-infected dogs. Vaccine X. 2019; 4:100048. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jvacx.\u003c/span\u003e\u003cspan address=\"https://doi.org/10.1016/j.jvacx.\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e2019.100048 [27] Velez R, G\u0026aacute;llego M. Commercially approved vaccines for canine leishmaniosis: a review of available data on their safety and efficacy. Trop Med Int Health. 2020;25:540\u0026ndash;557. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1111/tmi.13382\u003c/span\u003e\u003cspan address=\"10.1111/tmi.13382\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eShital S, Madan E, Selvapandiyan A, Kumar Ganguly N. An update on recombinant vaccines against leishmaniasis. Indian J Med Res. 2024;160:323\u0026ndash;337. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.25259/IJMR_1040_2024\u003c/span\u003e\u003cspan address=\"10.25259/IJMR_1040_2024\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eFern\u0026aacute;ndez Cotrina J, Iniesta V, Monroy I, Baz V, Hugnet C, Mara\u0026ntilde;on F, Fabra M, G\u0026oacute;mez-Nieto LC, Alonso C. A large-scale field randomized trial demonstrates safety and efficacy of the vaccine LetiFend\u0026reg; against canine leishmaniosis. Vaccine. 2018;36:1972\u0026ndash;1982. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.vaccine.2018.02.111\u003c/span\u003e\u003cspan address=\"10.1016/j.vaccine.2018.02.111\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMolano I, Alonso MG, Mir\u0026oacute;n C, Redondo E, Requena JM, Soto M, Nieto CG, Alonso C. A \u003cem\u003eLeishmania infantum\u003c/em\u003e multi-component antigenic protein mixed with live BCG confers protection to dogs experimentally infected with \u003cem\u003eL. infantum\u003c/em\u003e. Vet Immunol Immunopathol. 2003;92:1\u0026ndash;13. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/S0165-2427(02)00315-X\u003c/span\u003e\u003cspan address=\"10.1016/S0165-2427(02)00315-X\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCarcel\u0026eacute;n J, Iniesta V, Fern\u0026aacute;ndez-Cotrina J, Serrano F, Parejo JC, Corraliza I, Gallardo-Soler A, Mara\u0026ntilde;\u0026oacute;n F, Soto M, Alonso C, G\u0026oacute;mez-Nieto C. The chimerical multi-component Q protein from \u003cem\u003eLeishmania\u003c/em\u003e in the absence of adjuvant protects dogs against an experimental \u003cem\u003eLeishmania infantum\u003c/em\u003e infection. Vaccine. 2009; 27:5964\u0026ndash;73. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.vaccine.2009.07.069\u003c/span\u003e\u003cspan address=\"10.1016/j.vaccine.2009.07.069\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eFern\u0026aacute;ndez Cotrina J, Iniesta V, Monroy I, Baz V, Hugnet C, Mara\u0026ntilde;on F, Fabra M, G\u0026oacute;mez-Nieto LC, Alonso C. A large-scale field randomized trial demonstrates safety and efficacy of the vaccine LetiFend\u0026reg; against canine leishmaniosis. Vaccine. 2018; 36:1972\u0026ndash;1982. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.vaccine.2018.02.111\u003c/span\u003e\u003cspan address=\"10.1016/j.vaccine.2018.02.111\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eEuropean Medicines Agency. LetiFend\u0026reg;: Summary of Product Characteristics. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.ema.europa.eu/en/medicines/veterinary/EPAR/letifend\u003c/span\u003e\u003cspan address=\"https://www.ema.europa.eu/en/medicines/veterinary/EPAR/letifend\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLeite JC, Gon\u0026ccedil;alves AAM, de Oliveira DS, Resende LA, Boas DFV, Ribeiro HS, Pereira DFS, da Silva AV, Mariano RMDS, Reis PCC, Nakasone EN, Fran\u0026ccedil;a-Silva JC, Galdino AS, Paes PRO, Melo MM, Dias ES, Ch\u0026aacute;vez-Fumagalli MA, da Silveira-Lemos D, Dutra WO, Giunchetti RC. Transmission-Blocking Vaccines for Canine Visceral Leishmaniasis: New Progress and Yet New Challenges. Vaccines (Basel). 2023; 11:1565. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/vaccines11101565\u003c/span\u003e\u003cspan address=\"10.3390/vaccines11101565\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eReis AB, Giunchetti RC, Carrillo E, Martins-Filho OA, Moreno J. Immunity to \u003cem\u003eLeishmania\u003c/em\u003e and the rational search for vaccines against canine leishmaniasis. Trends Parasitol. 2010; 26:341\u0026ndash;9. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.pt.2010.04.005\u003c/span\u003e\u003cspan address=\"10.1016/j.pt.2010.04.005\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eFern\u0026aacute;ndez Cotrina J, Iniesta V, Monroy I, Baz V, Hugnet C, Mara\u0026ntilde;on F, Fabra M, G\u0026oacute;mez-Nieto LC, Alonso C. A large-scale field randomized trial demonstrates safety and efficacy of the vaccine LetiFend\u0026reg; against canine leishmaniosis. Vaccine. 2018; 36:1972\u0026ndash;1982. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.vaccine.2018.02.111\u003c/span\u003e\u003cspan address=\"10.1016/j.vaccine.2018.02.111\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eRegulation (EU) 2019/6 of the European Parliament and of the Council of 11 December 2018 on veterinary medicinal products and repealing Directive 2001/82/EC \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://eur-lex.europa.eu/eli/reg/2019/6/oj and/or https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32019R0006\u003c/span\u003e\u003cspan address=\"https://eur-lex.europa.eu/eli/reg/2019/6/oj and/or https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32019R0006\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eToepp A, Larson M, Grinnage-Pulley T, Bennett C, Anderson M, Parrish M, Fowler H, Wilson G, Gibson-Corely K, Gharpure R, Cotter C, Petersen C. Safety Analysis of \u003cem\u003eLeishmania\u003c/em\u003e Vaccine Used in a Randomized Canine Vaccine/Immunotherapy Trial. Am J Trop Med Hyg. 2018; 98:1332\u0026ndash;1338. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.4269/ajtmh.17-0888\u003c/span\u003e\u003cspan address=\"10.4269/ajtmh.17-0888\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCacheiro-Llaguno C, Parody N, Renshaw-Calder\u0026oacute;n A, Osuna C, Alonso C, Carn\u0026eacute;s J. Vaccination with LetiFend\u0026reg; reduces circulating immune complexes in dogs experimentally infected with \u003cem\u003eL. infantum\u003c/em\u003e. Vaccine. 2020; 38:890\u0026ndash;896. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.vaccine.2019.10.078\u003c/span\u003e\u003cspan address=\"10.1016/j.vaccine.2019.10.078\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMiles SA, Conrad SM, Alves RG, Jeronimo SM, Mosser DM. A role for IgG immune complexes during infection with the intracellular pathogen \u003cem\u003eLeishmania\u003c/em\u003e. J Exp Med. 2005; 201: 747\u0026ndash;54. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1084/jem.20041470\u003c/span\u003e\u003cspan address=\"10.1084/jem.20041470\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSch\u0026auml;fer I, M\u0026uuml;ller E, Naucke TJ. Ein update zur leishmaniose des hundes: diagnostik, therapie und monitoring. Tierarztl Prax Ausg K Klientiere Heimtiere 2022; 50(6): 431\u0026ndash;445. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://doi.org/10.1055/a-1970-9590\u003c/span\u003e\u003cspan address=\"10.1055/a-1970-9590\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Dog, Leishmaniasis therapy, Vaccination, immunomodulation, Letifend®","lastPublishedDoi":"10.21203/rs.3.rs-7886906/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7886906/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground:\u003c/strong\u003e Treatment of canine leishmaniasis (CanL), a severe infection caused by \u003cbr\u003e\n \u003cem\u003eL. infantum\u003c/em\u003e, is often challenging, e.g. fails due to the development of resistance of the pathogen to the medication and/or has severe side effects. Alternative treatment e.g. the use of immunomodulators has also been suggested and is already applied.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFindings:\u003c/strong\u003e Here, we report a case of a dog naturally infected by CanL, that was clinically in a severe life-threatend situation. The dog was vaccinated by a single dose of Letifend® and the dog recovered surprisingly well, within a couple of weeks. The clinical profile as well as parameters of clinical chemistry were recorded.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions:\u003c/strong\u003e Our results suggest that: 1) Vaccination with Letifend® can be used successfully to treat leishmaniasis. A surprisingly rapid improvement in the dog's general condition was observed \u003cbr\u003e\n2) Also laboratory parameters that are recorded long-term become normalized.\u003c/p\u003e","manuscriptTitle":"Therapeutic vaccination reverses severe canine leishmaniasis: a case report","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-26 00:29:52","doi":"10.21203/rs.3.rs-7886906/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"edd84da6-7983-4a37-886a-cfd32b0b1a4b","owner":[],"postedDate":"October 26th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-12-29T15:54:23+00:00","versionOfRecord":[],"versionCreatedAt":"2025-10-26 00:29:52","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7886906","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7886906","identity":"rs-7886906","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}