Description of Eimeria sameerensis n. sp. (Apicomplexa: Eimeriidae) from Domestic Sheep (Ovis aries) in the Semi-Arid Region of Marathwada, Maharashtra, India

Description of Eimeria sameerensis n. sp. (Apicomplexa: Eimeriidae) from Domestic Sheep (Ovis aries) in the Semi-Arid Region of Marathwada, Maharashtra, India | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Description of Eimeria sameerensis n. sp. (Apicomplexa: Eimeriidae) from Domestic Sheep (Ovis aries) in the Semi-Arid Region of Marathwada, Maharashtra, India Tejswini Sontakke, Ashwini Biradar, Dinesh Nalage This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9520439/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 6 You are reading this latest preprint version Abstract A parasitological investigation of domestic sheep ( Ovis aries ) was undertaken in Dharashiv district (Osmanabad), Maharashtra, India, from June 2013 to May 2015. A total of 2,911 fecal samples were examined, revealing 16 Eimeria taxa. Among these, one morphologically distinct, undescribed taxon was identified and is formally described here as Eimeria sameerensis n. sp. from sheep in the Marathwada region. Sporulated oocysts are elongated-oval with a bilayered wall, measuring 35.5 × 27.5 µm (range: 25.0–46.0 × 20.0–35.0 µm; L/W ratio 1.29). A well-defined micropyle and dome-shaped micropylar cap are present; oocystic residuum is absent and a single polar granule is consistently observed. Sporocysts measure 15.0 × 11.0 µm and bear a conspicuous crescent-shaped Stieda body with a compact granular residuum. Morphological differentiation from related ovine species ( E. ahsata, E. christenseni, E. parbhaniensis ) is based on oocyst dimensions, the number of refractile bodies per sporozoite, and Stieda body morphology. Sporulation is achieved within 48–72 h. This report constitutes the inaugural formal description of Eimeria sameerensis from sheep in India and enriches our knowledge of apicomplexan parasite biodiversity in the small ruminant fauna of Maharashtra. Eimeria sameerensis n. sp. Ovis aries coccidia Apicomplexa morphology India Figures Figure 1 Figure 2 1. Introduction Among gastrointestinal parasitic conditions of veterinary importance, coccidiosis caused by protozoan members of the genus Eimeria (Schneider, 1875; Phylum Apicomplexa, Family Eimeriidae) ranks among the foremost enteric afflictions of production animals across the globe(Sontakke et al., 2023 ). Affected animals suffer diarrhea, dehydration, reduced feed conversion, and retarded growth, with fatalities occurring predominantly among juveniles(Balicka-Ramisz, 1999 ; Chartier and Paraud, 2012 ; Foreyt, 1990 ; Taylor et al., 2016 ). Among ruminant hosts, sheep display marked vulnerability during the 4–6 month age window, a period when immune competence is still maturing and oocyst ingestion readily leads to patent disease(Jadhav, 2015 ). A defining biological feature of this genus is strict host specificity; most Eimeria species complete their entire endogenous cycle within a single host species(Levine, 1985 ). At least 17 valid species have so far been attributed to sheep worldwide. Within India, research concerning Eimeria diversity in livestock has largely centred on avian and bovine hosts; systematic surveys of ovine coccidians remain sparse, particularly in the Marathwada sub-region of Maharashtra(More et al., 2015 ; Nikam and Kanse, 2012 ; Sontakke et al., 2015 ). The present investigation was therefore undertaken to (i) assess the faunal composition of Eimeria taxa in domesticated sheep maintained in Dharashiv district (Osmanabad), Maharashtra, and (ii) provide a formal morphological account of a novel Eimeria taxon characterised on the basis of sporulated oocyst morphology, quantitative morphometry, and systematic comparison with previously described congeners. 2. Materials and Methods 2.1 Study area The investigation was carried out from July 2013 through June 2015 in Dharashiv district (Osmanabad), Maharashtra, India (coordinates: 18.2070° N, 76.1784° E). Collection sites encompassed village grazing areas as well as abattoir premises (Fig. 1 ). 2.2 Sample collection Fecal material was gathered from 2,911 individual sheep. Each fresh specimen was placed in a distinctly labeled sterile polythene bag, maintained at 4°C in an insulated container, and conveyed to the laboratory without delay (within 24 h). All samples underwent parasitological processing within five days of receipt to ensure oocyst integrity. 2.3 Oocyst isolation and flotation Fecal material (3–5 g per sample) was homogenized in distilled water, strained through double-layered muslin, and subjected to centrifugation (3,000 rpm, 10 min). Oocyst-enriched supernatants were obtained by resuspension of the pellet in saturated sodium chloride solution, and all oocyst-positive fractions were transferred to 2.5% potassium dichromate (K₂Cr₂O₇) for sporulation induction(Sontakke et al., 2021 ). 2.4 Sporulation and examination Sporulation was induced by incubating oocyst suspensions in 2.5% K₂Cr₂O₇ at 28–32°C under subdued illumination for a maximum of seven days. Progress was assessed at 12-h intervals until sporocyst formation exceeded 90%. Morphological examination was performed using compound light microscopy at 40× and 100× magnification, with linear measurements obtained via a calibrated ocular micrometer. Photodocumentation was achieved using a Sony DSC-WX200 (18.1 MP) digital camera (Eckert et al., 1995 ). 2.5 Identification and morphometrics Species-level identification was accomplished by applying published morphological and morphometric criteria. Characters evaluated included oocyst dimensions and shape index (L/W ratio), wall architecture, presence or absence of a micropyle and micropylar cap, polar granule number, oocystic residuum, sporocyst size and form, Stieda body prominence, sporocystic residuum character, and refractile body arrangement within sporozoites(Fayer, 1980 ; Taylor et al., 2016 ; Vercruysse, 1982 ) 3. Results Eimeria sameerensis n. sp. (Apicomplexa: Eimeriidae) 3.1 Description of Eimeria sameerensis n. sp. Type host: Ovis aries (Linnaeus, 1758) Type locality: Dharashiv district (Osmanabad), Maharashtra, India (18.2070° N, 76.1784° E) Prevalence: 2.0% (41 of 2,044 samples from sheep) Sporulation time: 48–72 h Site of infection: Unknown; oocysts recovered from feces Infective stage Transmission occurs via the fecal-oral route following ingestion of sporulated oocysts, which represent the environmentally stable, infective stage shed with fecal material Host-specific: Like most Eimeria species display strict host fidelity; the present taxon is accordingly regarded as host-specific to Ovis aries (Linnaeus, 1758). 3.2 Description of the sporulated oocyst: Oocysts elongated-oval, with a smooth bilayered wall approximately 1.5 µm in total thickness (outer layer 1.0 µm, yellowish and firm; inner layer 0.5 µm, pale and delicate); mean dimensions 35.5 × 27.5 µm (range: 25.0–46.0 × 20.0–35.0 µm); mean L/W ratio 1.29 (1.25–1.32). A distinct micropyle (2–8 µm wide) and dome-shaped micropylar cap (4–8 µm wide) are consistently present at the narrower pole. Oocystic residuum absent; a single conspicuous polar granule present in each oocyst. 3.3 Sporocyst and sporozoites : Sporocysts elongate-ovoid, measuring 15.0 × 11.0 µm on average (range: 12.0–18.0 × 9.0–13.0 µm; L/W ratio 1.36, range 1.33–1.38). Sporocyst wall single-layered (~ 0.4 µm thick); a well-developed, crescent-shaped Stieda body occupies the broader end; sub-Stieda and para-Stieda bodies are not observed. Sporocystic residuum compact and spheroidal (~ 3.2 µm diameter), composed of closely aggregated granules. Four elongate sporozoites per sporocyst; each sporozoite bears one anterior refractile body and two posterior refractile bodies, with the nucleus positioned slightly posterior to the cell midpoint. 3.4 Differential diagnosis : E. sameerensis n. sp. is distinguished from E. ahsata, E. christenseni , and E. parbhniensis by oocyst dimensions, the distinctive occurrence of three refractile bodies per sporozoite (one anterior plus two posterior, versus one anterior and one posterior in related taxa), and the markedly crescentic Stieda body absent or rudimentary in congeners. Additionally, sporulation to completion (48–72 h) proceeds more rapidly than in E. christenseni and E. parbhaniensis (96–120 h) (Fig. 2 & Table 1 ). Table 1 Comparison of morphological features of Eimeria sameerensis n. sp. and related species in sheep ( All measurements in µm ) Feature E. ahsata E. christenseni E. parbhaniensis E. sameerensis n. sp. Oocyst shape Ellipsoid Ovoid Elongate ovoid Elongate oval Oocyst size 27–42 × 16–25 30–44 × 20–31 29–52 × 22–39 25–46 × 20–35 (mean 35.5 × 27.5) Micropyle 4–9 µm wide 4–9 µm 7–13 µm 4–8 µm Micropylar cap 5–7 µm high 1–5 µm 2–5 µm 1–4 µm Polar granule Variable Absent Present One Oocyst residuum Absent Absent Absent Absent Sporocyst size 11–17 × 5–10 14–24 × 10–17 10–18 × 7–12 12–18 × 9–13 (mean 15 × 11) Stieda body Absent Small Present Prominent Sporocyst residuum Granular Granular Granular Compact, rounded Refractile bodies One small, one large One small, one large One small, one large Two large, one small Sporulation time (h) 60–84 96–120 72–120 48–72 Host Sheep Sheep Sheep Sheep 4. Discussion Systematic parasitological surveys conducted in Dharashiv district (Osmanabad) have yielded the inaugural record of Eimeria sameerensis n. sp. from ovine hosts in this part of Maharashtra. This finding expands the documented coccidian fauna of the Marathwada region, where earlier investigations have recorded E. parva, E. ninakohyakimovae , and E. ahsata (More et al., 2015 ; Sontakke and Nalage, 2021 ). Comparative morphometric evaluation clearly differentiates E. sameerensis from all ovine Eimeria congeners by a coherent combination of oocyst form, micropylar dimensions, and the distinctive three-refractile-body sporozoite configuration. The strict host-parasite association is concordant with well-established patterns within Eimeria , wherein species rarely cross host-species barriers among ruminants. E. sameerensis is presently regarded as endemic to sheep populations of the Dharashiv district. The site of endogenous development was not elucidated in this study, as only oocysts from fecal material were available; yet their occurrence firmly establishes intestinal infection. Future investigations employing 18S rRNA and COI gene sequencing should be prioritized to corroborate species delimitation and clarify the phylogenetic position of this taxon among ovine Eimeria species. 5. Conclusions The present investigation establishes Eimeria sameerensis n. sp. as a morphologically distinct coccidian taxon recovered from Ovis aries in Dharashiv district (Osmanabad), Maharashtra, India. Its differentiation from all previously described ovine Eimeria rests on a coherent suite of oocyst, sporocyst, and sporozoite characters. The present results draw attention to the incompletely characterised coccidian biodiversity within Eimeria infecting small ruminants in the Indian subcontinent and reinforce the importance of coupling classical morpho-taxonomy with molecular sequence data to unambiguously resolve species limits within this parasite genus. Declarations Ethical approval and consent to participate All fecal samples were collected non-invasively; therefore, ethical approval was not required. Consent for Publication Not Applicable Competing interests The authors declare no conflict of interest Funding The authors declare that no funds, grants, or other support were received during the preparation of this manuscript Author Contribution All authors wrote the main manuscript text and prepared figures. All authors reviewed the manuscript. All authors have equal contribution. Acknowledgments The authors thank the local livestock owners for access to sampling sites. We are very thankful to eminent professor S. V. Nikam, Department of Zoology, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad 431004, Maharashtra, India for valuable guidance on coccidian taxonomy, species identification, and confirmation. Availability of data and material Not Applicable References Balicka-Ramisz, A. (1999). Studies on coccidiosis in goats in Poland. Veterinary Parasitology , 81 (4), 347–349. https://doi.org/10.1016/S0304-4017(98)00258-1 Chartier, C. and Paraud, C. (2012). Coccidiosis due to Eimeria in sheep and goats, a review. Small Ruminant Research , 103 (1), 84–92. https://doi.org/10.1016/j.smallrumres.2011.10.022 Eckert, J., Braun, R. and Coudert, P. (1995). Guidelines on techniques in coccidiosis research . Fayer, R. (1980). Epidemiology of protozoan infections: The coccidia. Veterinary Parasitology , 6 (1–3), 75–103. https://doi.org/10.1016/0304-4017(80)90039-4 Foreyt, W. J. (1990). Coccidiosis and Cryptosporidiosis in Sheep and Goats. Veterinary Clinics of North America: Food Animal Practice , 6 (3), 655–670. https://doi.org/10.1016/S0749-0720(15)30838-0 Jadhav, B. (2015). Comparative Study of Seasonal Incidence of Chicken Coccidia in Gangapur and Vaijapur Tehsil of Aurangabad District in Maharashtra. Global Journal for Research Analysis , 4 (7), 10–11. Levine, N. D. (1985). Veterinary protozoology (illustrated ed.). Iowa State University Press, Ames. More, B.V., Lokhande, S.C. and Nikam, S.V. (2015). OBSERVATION OF EIMERIA PARVA IN GOAT AND SHEEP FROM BEED, M.S., INDIA. International Journal of Recent Scientific Research , 6 (3), 3076–3079. Nikam, S.V. and Kanse, V.S. (2012). COMPARATIVE STUDY OF SEASONAL INCIDENCE OF CHICKEN COCCIDIA IN EIGHT DISTRICTS OF MARATHWADA REGION (M.S.). Life Science Bulletin , 9 (2), 339–341. Sontakke, T.A. and Nalage, D. (2021). A Overview of Caprine Coccidiosis in Goat . Zenodo. https://doi.org/10.5281/ZENODO.7421638 Sontakke, T., Biradar, A. and Nalage, D. (2023). The role of genetics in determining resistance to coccidiosis in goats a review of current research and future directions. Molecular Biology Reports , 50 (7), 6171–6175. https://doi.org/10.1007/s11033-023-08520-3 Sontakke, T., Kanse, V., Bansode, V., Lokhande, S. and Nikam, S. (2015). Occurrence of Coccidian parasites in Sheep in Omerga region . https://doi.org/10.5281/ZENODO.17512454 Sontakke, T., Patil, K.T., Nalage, D. and Desale, N.S. (2021). Observation of coccidia (apicomplexa: eimeriidae) from goat (Capra hircus) family-bovidae from osmanabad district, (M.S.) India . https://doi.org/10.5281/ZENODO.7418013 Taylor, M.A., Coop, R. and Wall, R. (2016). Veterinary Parasitology (4th ed.). Wiley Blackwell. Vercruysse, J. (1982). The coccidia of sheep and goats in Senegal. Veterinary Parasitology , 10 (4), 297–306. https://doi.org/10.1016/0304-4017(82)90080-2 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 30 Apr, 2026 Reviewers agreed at journal 28 Apr, 2026 Reviewers invited by journal 27 Apr, 2026 Editor assigned by journal 25 Apr, 2026 Submission checks completed at journal 25 Apr, 2026 First submitted to journal 24 Apr, 2026 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. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-9520439","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":632662975,"identity":"e3921594-5540-4603-bfb2-d22a9341d9a7","order_by":0,"name":"Tejswini Sontakke","email":"","orcid":"","institution":"MGV’s MPH Mahila Mahavidyalaya","correspondingAuthor":false,"prefix":"","firstName":"Tejswini","middleName":"","lastName":"Sontakke","suffix":""},{"id":632662977,"identity":"e099c16b-a124-4fc9-a7bf-fc01f7ec8141","order_by":1,"name":"Ashwini Biradar","email":"","orcid":"","institution":"Dr. Babasaheb Ambedkar Marathwada University, Sub-Campus Osmanabad","correspondingAuthor":false,"prefix":"","firstName":"Ashwini","middleName":"","lastName":"Biradar","suffix":""},{"id":632662978,"identity":"099bae03-a734-443c-93b3-1b4a953c614f","order_by":2,"name":"Dinesh Nalage","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA/UlEQVRIiWNgGAWjYFAC5gYQwQMk2BgYKkBssAg+wIis5QyIzUicFgawFsY2uAhuYM5+sPHjlwprGXP29mePC+fVRvO3A7X8qNiGU4tlT2KztMyZdB7LnjPmxjO3Hc+dcZixgbHnzG2cWgwOJDZIS7Yd5jG4kcMmzbvtWG4DUAszYxseLecfNv+W/AfUcv/5M2neOcdy5xPUciOxTfJjA8gWBjNp3oaa3A2EtTxss2Y4ls5jcCbHTJrn2IHcjUAtB/H65Xzy4Zs/aqztDY4ffybNU1OXO+/84YMPflTg1gIC4HiEgsNg8gBe9UDA+APBriOkeBSMglEwCkYgAACzfF1GPCbwagAAAABJRU5ErkJggg==","orcid":"","institution":"Maulana Azad College of Arts, Science \u0026 Commerce","correspondingAuthor":true,"prefix":"","firstName":"Dinesh","middleName":"","lastName":"Nalage","suffix":""}],"badges":[],"createdAt":"2026-04-24 19:53:15","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9520439/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9520439/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":108592960,"identity":"4b5920d2-7b9a-4c03-af2a-202f5de95482","added_by":"auto","created_at":"2026-05-06 10:05:09","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":61215,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eMap of Dharashiv district (Osmanabad) showing sampling sites\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9520439/v1/6f0bc777f8234f8900425a69.jpg"},{"id":108804601,"identity":"9e3a15f4-ecd3-4330-aba3-0dd72feb3300","added_by":"auto","created_at":"2026-05-08 15:22:05","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":99347,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ea.\u003c/strong\u003e Unsporulated oocysts and \u003cstrong\u003eb.\u003c/strong\u003eSporulated oocysts of \u003cem\u003eEimeria sameerensis \u003c/em\u003en. sp.from sheep\u003cem\u003e \u003c/em\u003e(\u003cem\u003ea. \u003c/em\u003eMicropyalar cap; b. Micropyle; c. Outer layer; d. Inner layer, e. Sporoblast f. Cytoplasm g. sprocyst residuum h. Large refractile globule i. Small refractile globule, j. Steida body).\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9520439/v1/6cc03e977a87d64afb2d8dd0.jpg"},{"id":108812061,"identity":"d229287d-7a29-4e28-b098-c85b3c917865","added_by":"auto","created_at":"2026-05-08 16:08:50","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":390748,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9520439/v1/848f6524-6e94-4562-938f-f26247c1c035.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Description of Eimeria sameerensis n. sp. (Apicomplexa: Eimeriidae) from Domestic Sheep (Ovis aries) in the Semi-Arid Region of Marathwada, Maharashtra, India","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eAmong gastrointestinal parasitic conditions of veterinary importance, coccidiosis caused by protozoan members of the genus \u003cem\u003eEimeria\u003c/em\u003e (Schneider, 1875; Phylum Apicomplexa, Family Eimeriidae) ranks among the foremost enteric afflictions of production animals across the globe(Sontakke et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Affected animals suffer diarrhea, dehydration, reduced feed conversion, and retarded growth, with fatalities occurring predominantly among juveniles(Balicka-Ramisz, \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1999\u003c/span\u003e; Chartier and Paraud, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Foreyt, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e1990\u003c/span\u003e; Taylor et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). Among ruminant hosts, sheep display marked vulnerability during the 4\u0026ndash;6 month age window, a period when immune competence is still maturing and oocyst ingestion readily leads to patent disease(Jadhav, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). A defining biological feature of this genus is strict host specificity; most \u003cem\u003eEimeria\u003c/em\u003e species complete their entire endogenous cycle within a single host species(Levine, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e1985\u003c/span\u003e). At least 17 valid species have so far been attributed to sheep worldwide. Within India, research concerning \u003cem\u003eEimeria\u003c/em\u003e diversity in livestock has largely centred on avian and bovine hosts; systematic surveys of ovine coccidians remain sparse, particularly in the Marathwada sub-region of Maharashtra(More et al., \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Nikam and Kanse, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Sontakke et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). The present investigation was therefore undertaken to (i) assess the faunal composition of \u003cem\u003eEimeria\u003c/em\u003e taxa in domesticated sheep maintained in Dharashiv district (Osmanabad), Maharashtra, and (ii) provide a formal morphological account of a novel \u003cem\u003eEimeria\u003c/em\u003e taxon characterised on the basis of sporulated oocyst morphology, quantitative morphometry, and systematic comparison with previously described congeners.\u003c/p\u003e"},{"header":"2. Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Study area\u003c/h2\u003e \u003cp\u003eThe investigation was carried out from July 2013 through June 2015 in Dharashiv district (Osmanabad), Maharashtra, India (coordinates: 18.2070\u0026deg; N, 76.1784\u0026deg; E). Collection sites encompassed village grazing areas as well as abattoir premises (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Sample collection\u003c/h2\u003e \u003cp\u003eFecal material was gathered from 2,911 individual sheep. Each fresh specimen was placed in a distinctly labeled sterile polythene bag, maintained at 4\u0026deg;C in an insulated container, and conveyed to the laboratory without delay (within 24 h). All samples underwent parasitological processing within five days of receipt to ensure oocyst integrity.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Oocyst isolation and flotation\u003c/h2\u003e \u003cp\u003eFecal material (3\u0026ndash;5 g per sample) was homogenized in distilled water, strained through double-layered muslin, and subjected to centrifugation (3,000 rpm, 10 min). Oocyst-enriched supernatants were obtained by resuspension of the pellet in saturated sodium chloride solution, and all oocyst-positive fractions were transferred to 2.5% potassium dichromate (K₂Cr₂O₇) for sporulation induction(Sontakke et al., \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Sporulation and examination\u003c/h2\u003e \u003cp\u003eSporulation was induced by incubating oocyst suspensions in 2.5% K₂Cr₂O₇ at 28\u0026ndash;32\u0026deg;C under subdued illumination for a maximum of seven days. Progress was assessed at 12-h intervals until sporocyst formation exceeded 90%. Morphological examination was performed using compound light microscopy at 40\u0026times; and 100\u0026times; magnification, with linear measurements obtained via a calibrated ocular micrometer. Photodocumentation was achieved using a Sony DSC-WX200 (18.1 MP) digital camera (Eckert et al., \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e1995\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.5 Identification and morphometrics\u003c/h2\u003e \u003cp\u003eSpecies-level identification was accomplished by applying published morphological and morphometric criteria. Characters evaluated included oocyst dimensions and shape index (L/W ratio), wall architecture, presence or absence of a micropyle and micropylar cap, polar granule number, oocystic residuum, sporocyst size and form, Stieda body prominence, sporocystic residuum character, and refractile body arrangement within sporozoites(Fayer, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e1980\u003c/span\u003e; Taylor et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Vercruysse, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e1982\u003c/span\u003e)\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results","content":"\u003cp\u003e \u003cb\u003eEimeria sameerensis\u003c/b\u003e \u003cb\u003en. sp.\u003c/b\u003e\u003c/p\u003e \u003cp\u003e \u003cem\u003e(Apicomplexa: Eimeriidae)\u003c/em\u003e \u003c/p\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Description of \u003cem\u003eEimeria sameerensis\u003c/em\u003e n. sp.\u003c/h2\u003e \u003cp\u003eType host: \u003cem\u003eOvis aries\u003c/em\u003e (Linnaeus, 1758)\u003c/p\u003e \u003cp\u003eType locality: Dharashiv district (Osmanabad), Maharashtra, India (18.2070\u0026deg; N, 76.1784\u0026deg; E)\u003c/p\u003e \u003cp\u003ePrevalence: 2.0% (41 of 2,044 samples from sheep)\u003c/p\u003e \u003cp\u003eSporulation time: 48\u0026ndash;72 h\u003c/p\u003e \u003cp\u003eSite of infection: Unknown; oocysts recovered from feces\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eInfective stage\u003c/strong\u003e \u003cp\u003eTransmission occurs via the fecal-oral route following ingestion of sporulated oocysts, which represent the environmentally stable, infective stage shed with fecal material\u003c/p\u003e \u003c/p\u003e \u003cp\u003eHost-specific: Like most \u003cem\u003eEimeria\u003c/em\u003e species display strict host fidelity; the present taxon is accordingly regarded as host-specific to Ovis aries (Linnaeus, 1758).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Description of the sporulated oocyst:\u003c/h2\u003e \u003cp\u003eOocysts elongated-oval, with a smooth bilayered wall approximately 1.5 \u0026micro;m in total thickness (outer layer 1.0 \u0026micro;m, yellowish and firm; inner layer 0.5 \u0026micro;m, pale and delicate); mean dimensions 35.5 \u0026times; 27.5 \u0026micro;m (range: 25.0\u0026ndash;46.0 \u0026times; 20.0\u0026ndash;35.0 \u0026micro;m); mean L/W ratio 1.29 (1.25\u0026ndash;1.32). A distinct micropyle (2\u0026ndash;8 \u0026micro;m wide) and dome-shaped micropylar cap (4\u0026ndash;8 \u0026micro;m wide) are consistently present at the narrower pole. Oocystic residuum absent; a single conspicuous polar granule present in each oocyst.\u003c/p\u003e \u003cp\u003e \u003cb\u003e3.3 Sporocyst and sporozoites\u003c/b\u003e: Sporocysts elongate-ovoid, measuring 15.0 \u0026times; 11.0 \u0026micro;m on average (range: 12.0\u0026ndash;18.0 \u0026times; 9.0\u0026ndash;13.0 \u0026micro;m; L/W ratio 1.36, range 1.33\u0026ndash;1.38). Sporocyst wall single-layered (~\u0026thinsp;0.4 \u0026micro;m thick); a well-developed, crescent-shaped Stieda body occupies the broader end; sub-Stieda and para-Stieda bodies are not observed. Sporocystic residuum compact and spheroidal (~\u0026thinsp;3.2 \u0026micro;m diameter), composed of closely aggregated granules. Four elongate sporozoites per sporocyst; each sporozoite bears one anterior refractile body and two posterior refractile bodies, with the nucleus positioned slightly posterior to the cell midpoint.\u003c/p\u003e \u003cp\u003e \u003cb\u003e3.4 Differential diagnosis\u003c/b\u003e: \u003cem\u003eE. sameerensis\u003c/em\u003e n. sp. is distinguished from \u003cem\u003eE. ahsata, E. christenseni\u003c/em\u003e, and \u003cem\u003eE. parbhniensis\u003c/em\u003e by oocyst dimensions, the distinctive occurrence of three refractile bodies per sporozoite (one anterior plus two posterior, versus one anterior and one posterior in related taxa), and the markedly crescentic Stieda body absent or rudimentary in congeners. Additionally, sporulation to completion (48\u0026ndash;72 h) proceeds more rapidly than in \u003cem\u003eE. christenseni\u003c/em\u003e and \u003cem\u003eE. parbhaniensis\u003c/em\u003e (96\u0026ndash;120 h) (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e \u003cb\u003e\u0026amp;\u003c/b\u003e Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eTable 1 Comparison of morphological features of \u003cem\u003eEimeria sameerensis\u003c/em\u003e n. sp. and related species in sheep \u003cem\u003e(\u003c/em\u003eAll measurements in \u0026micro;m\u003cem\u003e)\u003c/em\u003e\u003c/p\u003e\u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Taba\" border=\"1\"\u003e \u003ccolgroup cols=\"5\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFeature\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003eE. ahsata\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eE. christenseni\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eE. parbhaniensis\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003eE. sameerensis\u003c/em\u003e\u0026nbsp;n. sp.\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eOocyst shape\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEllipsoid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eOvoid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eElongate ovoid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eElongate oval\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eOocyst size\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e27\u0026ndash;42 \u0026times; 16\u0026ndash;25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e30\u0026ndash;44 \u0026times; 20\u0026ndash;31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e29\u0026ndash;52 \u0026times; 22\u0026ndash;39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e25\u0026ndash;46 \u0026times; 20\u0026ndash;35 (mean 35.5 \u0026times; 27.5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eMicropyle\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4\u0026ndash;9 \u0026micro;m wide\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4\u0026ndash;9 \u0026micro;m\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7\u0026ndash;13 \u0026micro;m\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4\u0026ndash;8 \u0026micro;m\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eMicropylar cap\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u0026ndash;7 \u0026micro;m high\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u0026ndash;5 \u0026micro;m\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2\u0026ndash;5 \u0026micro;m\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1\u0026ndash;4 \u0026micro;m\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePolar granule\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAbsent\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePresent\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eOne\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eOocyst residuum\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAbsent\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAbsent\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eAbsent\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eAbsent\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSporocyst size\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11\u0026ndash;17 \u0026times; 5\u0026ndash;10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14\u0026ndash;24 \u0026times; 10\u0026ndash;17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10\u0026ndash;18 \u0026times; 7\u0026ndash;12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e12\u0026ndash;18 \u0026times; 9\u0026ndash;13 (mean 15 \u0026times; 11)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eStieda body\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAbsent\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSmall\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePresent\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eProminent\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSporocyst residuum\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGranular\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGranular\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eGranular\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eCompact, rounded\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eRefractile bodies\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOne small, one large\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eOne small, one large\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOne small, one large\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eTwo large, one small\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSporulation time (h)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e60\u0026ndash;84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e96\u0026ndash;120\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e72\u0026ndash;120\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e48\u0026ndash;72\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHost\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSheep\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSheep\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSheep\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSheep\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eSystematic parasitological surveys conducted in Dharashiv district (Osmanabad) have yielded the inaugural record of \u003cem\u003eEimeria sameerensis\u003c/em\u003e n. sp. from ovine hosts in this part of Maharashtra. This finding expands the documented coccidian fauna of the Marathwada region, where earlier investigations have recorded \u003cem\u003eE. parva, E. ninakohyakimovae\u003c/em\u003e, and \u003cem\u003eE. ahsata\u003c/em\u003e(More et al., \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Sontakke and Nalage, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Comparative morphometric evaluation clearly differentiates \u003cem\u003eE. sameerensis\u003c/em\u003e from all ovine Eimeria congeners by a coherent combination of oocyst form, micropylar dimensions, and the distinctive three-refractile-body sporozoite configuration. The strict host-parasite association is concordant with well-established patterns within \u003cem\u003eEimeria\u003c/em\u003e, wherein species rarely cross host-species barriers among ruminants. \u003cem\u003eE. sameerensis\u003c/em\u003e is presently regarded as endemic to sheep populations of the Dharashiv district. The site of endogenous development was not elucidated in this study, as only oocysts from fecal material were available; yet their occurrence firmly establishes intestinal infection. Future investigations employing 18S rRNA and COI gene sequencing should be prioritized to corroborate species delimitation and clarify the phylogenetic position of this taxon among ovine \u003cem\u003eEimeria\u003c/em\u003e species.\u003c/p\u003e"},{"header":"5. Conclusions","content":"\u003cp\u003eThe present investigation establishes \u003cem\u003eEimeria sameerensis\u003c/em\u003e n. sp. as a morphologically distinct coccidian taxon recovered from \u003cem\u003eOvis aries\u003c/em\u003e in Dharashiv district (Osmanabad), Maharashtra, India. Its differentiation from all previously described ovine Eimeria rests on a coherent suite of oocyst, sporocyst, and sporozoite characters. The present results draw attention to the incompletely characterised coccidian biodiversity within \u003cem\u003eEimeria\u003c/em\u003e infecting small ruminants in the Indian subcontinent and reinforce the importance of coupling classical morpho-taxonomy with molecular sequence data to unambiguously resolve species limits within this parasite genus.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eEthical approval and consent to participate\u003c/h2\u003e \u003cp\u003eAll fecal samples were collected non-invasively; therefore, ethical approval was not 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 conflict of interest\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eThe authors declare that no funds, grants, or other support were received during the preparation of this manuscript\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eAll authors wrote the main manuscript text and prepared figures. All authors reviewed the manuscript. All authors have equal contribution.\u003c/p\u003e\u003ch2\u003eAcknowledgments\u003c/h2\u003e \u003cp\u003eThe authors thank the local livestock owners for access to sampling sites. We are very thankful to eminent professor S. V. Nikam, Department of Zoology, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad 431004, Maharashtra, India for valuable guidance on coccidian taxonomy, species identification, and confirmation.\u003c/p\u003e\u003ch2\u003eAvailability of data and material\u003c/h2\u003e \u003cp\u003eNot Applicable\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eBalicka-Ramisz, A. (1999). Studies on coccidiosis in goats in Poland. \u003cem\u003eVeterinary Parasitology\u003c/em\u003e, \u003cem\u003e81\u003c/em\u003e(4), 347\u0026ndash;349. https://doi.org/10.1016/S0304-4017(98)00258-1\u003c/li\u003e\n\u003cli\u003eChartier, C. and Paraud, C. (2012). Coccidiosis due to Eimeria in sheep and goats, a review. \u003cem\u003eSmall Ruminant Research\u003c/em\u003e, \u003cem\u003e103\u003c/em\u003e(1), 84\u0026ndash;92. https://doi.org/10.1016/j.smallrumres.2011.10.022\u003c/li\u003e\n\u003cli\u003eEckert, J., Braun, R. and Coudert, P. (1995). \u003cem\u003eGuidelines on techniques in coccidiosis research\u003c/em\u003e.\u003c/li\u003e\n\u003cli\u003eFayer, R. (1980). Epidemiology of protozoan infections: The coccidia. \u003cem\u003eVeterinary Parasitology\u003c/em\u003e, \u003cem\u003e6\u003c/em\u003e(1\u0026ndash;3), 75\u0026ndash;103. https://doi.org/10.1016/0304-4017(80)90039-4\u003c/li\u003e\n\u003cli\u003eForeyt, W. J. (1990). Coccidiosis and Cryptosporidiosis in Sheep and Goats. \u003cem\u003eVeterinary Clinics of North America: Food Animal Practice\u003c/em\u003e, \u003cem\u003e6\u003c/em\u003e(3), 655\u0026ndash;670. https://doi.org/10.1016/S0749-0720(15)30838-0\u003c/li\u003e\n\u003cli\u003eJadhav, B. (2015). Comparative Study of Seasonal Incidence of Chicken Coccidia in Gangapur and Vaijapur Tehsil of Aurangabad District in Maharashtra. \u003cem\u003eGlobal Journal for Research Analysis\u003c/em\u003e, \u003cem\u003e4\u003c/em\u003e(7), 10\u0026ndash;11.\u003c/li\u003e\n\u003cli\u003eLevine, N. D. (1985). \u003cem\u003eVeterinary protozoology\u003c/em\u003e (illustrated ed.). Iowa State University Press, Ames.\u003c/li\u003e\n\u003cli\u003eMore, B.V., Lokhande, S.C. and Nikam, S.V. (2015). OBSERVATION OF EIMERIA PARVA IN GOAT AND SHEEP FROM BEED, M.S., INDIA. \u003cem\u003eInternational Journal of Recent Scientific Research\u003c/em\u003e, \u003cem\u003e6\u003c/em\u003e(3), 3076\u0026ndash;3079.\u003c/li\u003e\n\u003cli\u003eNikam, S.V. and Kanse, V.S. (2012). COMPARATIVE STUDY OF SEASONAL INCIDENCE OF CHICKEN COCCIDIA IN EIGHT DISTRICTS OF MARATHWADA REGION (M.S.). \u003cem\u003eLife Science Bulletin\u003c/em\u003e, \u003cem\u003e9\u003c/em\u003e(2), 339\u0026ndash;341.\u003c/li\u003e\n\u003cli\u003eSontakke, T.A. and Nalage, D. (2021). \u003cem\u003eA Overview of Caprine Coccidiosis in Goat\u003c/em\u003e. Zenodo. https://doi.org/10.5281/ZENODO.7421638 \u003c/li\u003e\n\u003cli\u003eSontakke, T., Biradar, A. and Nalage, D. (2023). The role of genetics in determining resistance to coccidiosis in goats a review of current research and future directions. \u003cem\u003eMolecular Biology Reports\u003c/em\u003e, \u003cem\u003e50\u003c/em\u003e(7), 6171\u0026ndash;6175. https://doi.org/10.1007/s11033-023-08520-3\u003c/li\u003e\n\u003cli\u003eSontakke, T., Kanse, V., Bansode, V., Lokhande, S. and Nikam, S. (2015). \u003cem\u003eOccurrence of Coccidian parasites in Sheep in Omerga region\u003c/em\u003e. https://doi.org/10.5281/ZENODO.17512454\u003c/li\u003e\n\u003cli\u003eSontakke, T., Patil, K.T., Nalage, D. and Desale, N.S. (2021). \u003cem\u003eObservation of coccidia (apicomplexa: eimeriidae) from goat (Capra hircus) family-bovidae from osmanabad district, (M.S.) India\u003c/em\u003e. https://doi.org/10.5281/ZENODO.7418013\u003c/li\u003e\n\u003cli\u003eTaylor, M.A., Coop, R. and Wall, R. (2016). \u003cem\u003eVeterinary Parasitology\u003c/em\u003e (4th ed.). Wiley Blackwell.\u003c/li\u003e\n\u003cli\u003eVercruysse, J. (1982). The coccidia of sheep and goats in Senegal. \u003cem\u003eVeterinary Parasitology\u003c/em\u003e, \u003cem\u003e10\u003c/em\u003e(4), 297\u0026ndash;306. https://doi.org/10.1016/0304-4017(82)90080-2\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"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":"systematic-parasitology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Systematic Parasitology](https://www.springer.com/journal/11230)","snPcode":"11230","submissionUrl":"https://submission.nature.com/new-submission/11230/3","title":"Systematic Parasitology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Eimeria sameerensis n. sp., Ovis aries, coccidia, Apicomplexa, morphology, India","lastPublishedDoi":"10.21203/rs.3.rs-9520439/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9520439/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eA parasitological investigation of domestic sheep (\u003cem\u003eOvis aries\u003c/em\u003e) was undertaken in Dharashiv district (Osmanabad), Maharashtra, India, from June 2013 to May 2015. A total of 2,911 fecal samples were examined, revealing 16 \u003cem\u003eEimeria\u003c/em\u003e taxa. Among these, one morphologically distinct, undescribed taxon was identified and is formally described here as \u003cem\u003eEimeria sameerensis\u003c/em\u003e n. sp. from sheep in the Marathwada region. Sporulated oocysts are elongated-oval with a bilayered wall, measuring 35.5 \u0026times; 27.5 \u0026micro;m (range: 25.0\u0026ndash;46.0 \u0026times; 20.0\u0026ndash;35.0 \u0026micro;m; L/W ratio 1.29). A well-defined micropyle and dome-shaped micropylar cap are present; oocystic residuum is absent and a single polar granule is consistently observed. Sporocysts measure 15.0 \u0026times; 11.0 \u0026micro;m and bear a conspicuous crescent-shaped Stieda body with a compact granular residuum. Morphological differentiation from related ovine species (\u003cem\u003eE. ahsata, E. christenseni, E. parbhaniensis\u003c/em\u003e) is based on oocyst dimensions, the number of refractile bodies per sporozoite, and Stieda body morphology. Sporulation is achieved within 48\u0026ndash;72 h. This report constitutes the inaugural formal description of \u003cem\u003eEimeria sameerensis\u003c/em\u003e from sheep in India and enriches our knowledge of apicomplexan parasite biodiversity in the small ruminant fauna of Maharashtra.\u003c/p\u003e","manuscriptTitle":"Description of Eimeria sameerensis n. sp. 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