First Epidemiological Assessment: Syphilis Seroprevalence among Asymptomatic Blood Donors in Merowe, Northern Sudan, 2022

First Epidemiological Assessment: Syphilis Seroprevalence among Asymptomatic Blood Donors in Merowe, Northern Sudan, 2022 | 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 First Epidemiological Assessment: Syphilis Seroprevalence among Asymptomatic Blood Donors in Merowe, Northern Sudan, 2022 Hamad A. Albagir, Doaa Albagir Ahmed, Sabra Alfadil Ibrahim, Hiba Elsadig Salah This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8787035/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: Syphilis remains a significant transfusion-transmissible infection, yet regional epidemiological data in Sudan is sparse. The Northern State, particularly Merowe, lacks prior seroprevalence studies despite significant demographic shifts following the Merowe Dam construction. This study aimed to establish the first baseline syphilis prevalence among asymptomatic blood donors in this underrepresented region. Methods: A cross-sectional study was conducted in January 2022 at the Merowe blood donation center. Eighty-nine consecutive asymptomatic male blood donors were screened for anti-Treponema pallidum antibodies using a commercial Enzyme-Linked Immunosorbent Assay (ELISA) kit. Demographic and clinical data were collected via structured questionnaire. Results: The overall seroprevalence was 2.25% (2/89). The donor population median age was 32 years (range: 18–64). Statistical analysis yielded an odds ratio of 0.02, relative risk of 0.04, 95% confidence interval 0.01–0.1, and p-value <0.0001. Conclusion: This is the first syphilis seroprevalence report from Merowe, revealing a lower rate compared to other Sudanese regions but higher than the global average. The findings fill a critical geographical data gap, support evidence-based blood safety strategies, and underscore the need for localized surveillance in demographically dynamic regions. Pathology Syphilis Treponema pallidum blood donors seroprevalence transfusion-transmissible infections Sudan Northern State ELISA Figures Figure 1 Figure 2 Figure 3 1. Introduction Blood transfusion is a vital therapeutic intervention but carries risks of transmitting infectious agents, including hepatitis B and C viruses (HBV, HCV), human immunodeficiency virus (HIV), and syphilis [ 1 , 2 ]. Syphilis, caused by the spirochete Treponema pallidum subsp. pallidum, remains a global health challenge, with an estimated 6 million new cases annually [ 3 , 4 ]. Although T. pallidum is susceptible to cold storage, transfusion transmission can occur particularly with fresh blood or platelet components warning continuous screening in blood banks [ 5 , 6 ]. The World Health Organization (WHO) estimates syphilis accounts for approximately 10% of sexually transmitted infections worldwide [ 7 , 8 ]. In Sudan, routine screening for transfusion-transmissible infections (TTIs) is mandatory, yet epidemiological data on syphilis among blood donors remains limited and regionally variable. Prior studies report prevalence ranging from 3.7% in Khartoum [ 11 ] to 13% in North Darfur State [ 12 ]. There are, however, no published data from the Northern State specifically Merowe, an area that has experienced notable demographic changes following the completion of the Merowe Dam. This study therefore aimed to determine the seroprevalence of syphilis among asymptomatic blood donors in Merowe, Northern Sudan, to establish a regional baseline, inform blood safety protocols, and contribute to national epidemiological mapping. 2. Methods 2.1. Study Design and Setting A descriptive cross-sectional study was conducted in January 2022 at the Merowe Blood Donation Center, Northern State, Sudan. Merowe is located approximately 330 km north of Khartoum and serves as a referral hub for surrounding communities. 2.2. Study Population Eligible participants were consecutive asymptomatic male blood donors who met national donation criteria and provided informed consent. Exclusion criteria included age <22 years, signs of acute illness, or refusal to participate. A total of 89 donors were enrolled using probability sampling. 2.3. Data Collection A pre-coded questionnaire collected data on: Demographic characteristics (age, residence) Donation history (first-time vs. repeat donor) Health status and transfusion history 2.4. Laboratory Analysis Approximately 3–5 mL of venous blood was collected from each donor. Serum was separated and tested for anti-T. Pallidum IgG and IgM antibodies using a commercial ELISA kit (Fortress Diagnostics, UK) following manufacturer instructions. 2.5. Data Analysis Data were analyzed using SPSS version 20.0. Descriptive statistics were presented as frequencies and percentages. Seroprevalence was calculated as (number positive / total tested) × 100. Associations were assessed using odds ratios, relative risk, 95% confidence intervals, and p-values (significance at p < 0.05). 2.6. Ethical Approval The study was approved by the ethical review board of Abdulatif Alhamed University of Technology. Written informed consent was obtained from all participants. Confidentiality was assured, and reactive donors were referred for clinical management. 3. Results 3.1. Demographic Characteristics All 89 participants were male Sudanese nationals from Northern State. Age distribution is shown in Table 1 and visualized in Figure 1. Table 1: Age Distribution of Study Participants (n = 89) Age Group (Years) Number Percentage (%) 18-25 34 38.2 26-35 42 47.2 36-45 13 14.6 Total 89 100.0 Figure 1: Age Distribution of Blood Donors Figure 1 illustrates the age distribution of the 89 blood donors included in the study, showing the highest representation in the 26-35 years age group. 3.2. Syphilis Seroprevalence Overall seroprevalence was 2.25% (2/89). Both reactive donors were adult males. Results are summarized in Table 2 and Figure 2. Table 2: Seroprevalence of Syphilis Among Donors Syphilis Status Number Percentage (%) Positive 2 2.25 Negative 87 97.75 Total 89 100.0 Figure 2: Seroprevalence of Syphilis among Donors Figure 2 shows the overall seroprevalence of syphilis, with only 2.25% of donors testing positive for anti-Treponema pallidum antibodies. 3.3. Statistical Analysis Key statistical measures are presented in Table 3. Table 3: Statistical Measures of Syphilis Seroprevalence Statistical Measure Value Prevalence 2.25% (2/89) Odds Ratio 0.02 Relative Risk 0.04 95% Confidence Interval 0.01 - 0.1 P-value <0.0001 4. Discussion This study provides the first seroprevalence estimate of syphilis among blood donors in Merowe, Northern Sudan. The observed prevalence of 2.25% is lower than rates reported from other Sudanese regions—such as 13% in North Darfur [12] and 3.7% in Khartoum [11]—yet remains higher than the global average of approximately 0.5% [20]. Geographical variation may reflect differences in sexual health awareness, accessibility of health services, cultural norms, or effectiveness of donor screening programs. The relatively low prevalence in Merowe could be influenced by recent demographic shifts post-dam construction, potentially altering local transmission dynamics. Comparative Analysis: Regional and Global Context Figure 3 illustrates how Merowe’s prevalence situates within regional and global contexts: Figure 3: Comparative Syphilis Seroprevalence across Regions (%) Figure 3 provides a visual comparison of syphilis seroprevalence rates across different regions, contextualizing the Merowe finding within broader epidemiological patterns. The lower prevalence in Merowe compared to other high-burden regions in Sudan suggests potential success in local health interventions or unique socio-demographic buffers. Nevertheless, the rate exceeding the global average underscores the continued relevance of syphilis screening in Sudanese blood banks. Strengths and Limitations Strengths include the use of standardized ELISA testing and ethical compliance. Limitations are the small sample size, exclusive male cohort, cross-sectional design, and lack of confirmatory testing (e.g., TPHA) to differentiate active from past infection. Public Health Implications These findings: Provide a baseline for future surveillance in Northern State. Support the necessity of sustained mandatory syphilis screening. Highlight opportunities for integrated donor education on sexual health. Emphasize the value of decentralized data in shaping national blood safety policies. 5. Conclusion This first epidemiological assessment from Merowe, Northern Sudan, documents a syphilis seroprevalence of 2.25% among asymptomatic male blood donors. Although lower than other Sudanese regions, the rate remains above global averages, justifying continued screening. The study fills a critical data gap and offers a benchmark for monitoring trends, evaluating interventions, and informing evidence-based blood safety strategies in similar transitional settings. Declarations Ethics approval and consent to participate: Approved by Abdulatif Alhamed University of Technology. Written informed consent was obtained from all participants. Consent for publication: Not applicable. Availability of data and materials: Available from the corresponding author upon reasonable request. Competing interests: The authors declare no competing interests. Funding: This research received no external funding. Authors' contributions: D.A.A.: Conceptualization, Methodology, Investigation, Formal Analysis, And Writing Original Draft. S.A.I.: Investigation, Validation, Writing – Review & Editing. H.E.S.: Investigation, Resources, Writing – Review & Editing. H.A.A.: Conceptualization, Supervision, Project Administration, Writing – Review & Editing. All authors read and approved the final manuscript. Acknowledgements: We thank the staff of Merowe Blood Donation Center and Abdulatif Alhamed University of Technology for their support. References Grenache A, et al. A population-based longitudinal study on demographic changes and blood demand. Blood Adv. 2017;1(14):867–74. Yu C, et al. Institutional incentives for altruism: gifting blood in China. BMC Public Health. 2013;13:524. Plafond RE, Luke hart SA. Biological basis for syphilis. Clin Microbiol Rev. 2006;19(1):29–49. Brigitte C, et al. Interaction of Treponema pallidum with human platelets. PLoS One. 2019;14(1):e0210902. Katz LM, et al. Transfusion-transmitted syphilis: still a risk? Transfusion. 2019;59(11):3263–6. Kitchen AD, Barbara JA. Syphilis and blood donation: is there a risk? Transfus Med. 2018;28(3):243–51. Rolfs RT. Treatment of syphilis. Clin Infect Dis. 1995;20(Suppl 1):S23–38. Kitayama K, et al. Syphilis in the Americas: a systematic review protocol. Syst Rev. 2017;6(1):195. Federal Ministry of Health. National HIV and syphilis sero-behavioral survey in Sudan. Khartoum; 2018. Rahlenbeck SI, et al. Infection with HIV, syphilis and HBV in Ethiopia. Int J STD AIDS. 1997;8:261–4. Elsheikh SM, et al. Sero-prevalence of TTIs at Central Blood Bank, Khartoum. Afr J Lab Med. 2020;9(1):987. Adam NK, et al. Seroprevalence of syphilis among donors in North Darfur. J Microbiol Exp. 2021;9(2):42–5. Rahlenbeck SI, et al. (as above). Quintas E. Prevalence of syphilis in blood donors in Angola, 2011–2016. Clin Med Rep. 2018;2(1):1–4. Mavenyengwa RT, et al. Prevalence of HIV, syphilis, HBV, HCV in Namibian donors. BMC Public Health. 2014;14:424. Siraj N, et al. Seroprevalence of TTIs in Eritrea. BMC Infect Dis. 2018;18(1):264. Olokoba AB, et al. Syphilis in voluntary donors in Nigeria. Eur J Sci Res. 2009;31(3):335–8. Elyamany G, et al. Syphilis prevalence among donors in Saudi Arabia. Electron Physician. 2016;8(8):2747–51. Chaudhary V, et al. Seroprevalence of TTIs in Uttar Pradesh. Int J Med Sci Public Health. 2014;3(11):1381–4. Newman L, et al. Global estimates of STI prevalence and incidence. PLoS One. 2015;10:e0143304. Additional Declarations The authors declare no competing interests. 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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-8787035","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":585734846,"identity":"5a8c79a5-069d-475e-b340-72e2128ac4a2","order_by":0,"name":"Hamad A. 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representation in the 26-35 years age group.\u003c/em\u003e\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-8787035/v1/39ca0fa96b9b065e4d22e04b.png"},{"id":101961684,"identity":"692ff435-365e-404f-a91a-33de27643e62","added_by":"auto","created_at":"2026-02-05 12:45:40","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":42435,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSeroprevalence of Syphilis among Donors\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eFigure 2 shows the overall seroprevalence of syphilis, with only 2.25% of donors testing positive for anti-Treponema pallidum antibodies.\u003c/em\u003e\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-8787035/v1/1016e9be6c26d15365e50a1a.png"},{"id":101961686,"identity":"a2165084-0bb2-43b4-8f62-c5687d127e60","added_by":"auto","created_at":"2026-02-05 12:45:41","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":82451,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eComparative Syphilis Seroprevalence across Regions (%)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eFigure 3 provides a visual comparison of syphilis seroprevalence rates across different regions, contextualizing the Merowe finding within broader epidemiological patterns.\u003c/em\u003e\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-8787035/v1/775300f922e69cc6052c6314.png"},{"id":102298668,"identity":"49d88078-a1a6-46e4-9659-2d195e07e066","added_by":"auto","created_at":"2026-02-10 10:57:41","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":963824,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8787035/v1/4f9f70ff-c0fd-43b7-9990-5647379a963e.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003e\u003cstrong\u003eFirst Epidemiological Assessment: Syphilis Seroprevalence among Asymptomatic Blood Donors in Merowe, Northern Sudan, 2022\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eBlood transfusion is a vital therapeutic intervention but carries risks of transmitting infectious agents, including hepatitis B and C viruses (HBV, HCV), human immunodeficiency virus (HIV), and syphilis [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Syphilis, caused by the spirochete Treponema pallidum subsp. pallidum, remains a global health challenge, with an estimated 6\u0026nbsp;million new cases annually [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAlthough T. pallidum is susceptible to cold storage, transfusion transmission can occur particularly with fresh blood or platelet components warning continuous screening in blood banks [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. The World Health Organization (WHO) estimates syphilis accounts for approximately 10% of sexually transmitted infections worldwide [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn Sudan, routine screening for transfusion-transmissible infections (TTIs) is mandatory, yet epidemiological data on syphilis among blood donors remains limited and regionally variable. Prior studies report prevalence ranging from 3.7% in Khartoum [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e] to 13% in North Darfur State [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. There are, however, no published data from the Northern State specifically Merowe, an area that has experienced notable demographic changes following the completion of the Merowe Dam.\u003c/p\u003e \u003cp\u003eThis study therefore aimed to determine the seroprevalence of syphilis among asymptomatic blood donors in Merowe, Northern Sudan, to establish a regional baseline, inform blood safety protocols, and contribute to national epidemiological mapping.\u003c/p\u003e"},{"header":"2. Methods","content":"\u003cp\u003e\u003cstrong\u003e2.1. Study Design and Setting\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA descriptive cross-sectional study was conducted in January 2022 at the Merowe Blood Donation Center, Northern State, Sudan. Merowe is located approximately 330 km north of Khartoum and serves as a referral hub for surrounding communities.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.2. Study Population\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eEligible participants were consecutive asymptomatic male blood donors who met national donation criteria and provided informed consent. Exclusion criteria included age \u0026lt;22 years, signs of acute illness, or refusal to participate.\u003c/p\u003e\n\u003cp\u003eA total of 89 donors were enrolled using probability sampling.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.3. Data Collection\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA pre-coded questionnaire collected data on:\u003c/p\u003e\n\u003cul\u003e\n \u003cli\u003eDemographic characteristics (age, residence)\u003c/li\u003e\n \u003cli\u003eDonation history (first-time vs. repeat donor)\u003c/li\u003e\n \u003cli\u003eHealth status and transfusion history\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003e2.4. Laboratory Analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eApproximately 3–5 mL of venous blood was collected from each donor. Serum was separated and tested for anti-T. Pallidum IgG and IgM antibodies using a commercial ELISA kit (Fortress Diagnostics, UK) following manufacturer instructions.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.5. Data Analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData were analyzed using SPSS version 20.0. Descriptive statistics were presented as frequencies and percentages. Seroprevalence was calculated as (number positive / total tested) × 100. Associations were assessed using odds ratios, relative risk, 95% confidence intervals, and p-values (significance at p \u0026lt; 0.05).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.6. Ethical Approval\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study was approved by the ethical review board of Abdulatif Alhamed University of Technology. Written informed consent was obtained from all participants. Confidentiality was assured, and reactive donors were referred for clinical management.\u003c/p\u003e"},{"header":"3. Results","content":"\u003cp\u003e\u003cstrong\u003e3.1. Demographic Characteristics\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll 89 participants were male Sudanese nationals from Northern State. Age distribution is shown in Table 1 and visualized in Figure 1.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1: Age Distribution of Study Participants (n = 89)\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"463\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAge Group (Years)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eNumber\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePercentage (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e18-25\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e38.2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e26-35\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e47.2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e36-45\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e14.6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTotal\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e89\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e100.0\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003cstrong\u003eFigure 1: Age Distribution of Blood Donors\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eFigure 1 illustrates the age distribution of the 89 blood donors included in the study, showing the highest representation in the 26-35 years age group.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.2. Syphilis Seroprevalence\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOverall seroprevalence was 2.25% (2/89). Both reactive donors were adult males. Results are summarized in Table 2 and Figure 2.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2: Seroprevalence of Syphilis Among Donors\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"378\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSyphilis Status\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eNumber\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePercentage (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePositive\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e2.25\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eNegative\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e87\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e97.75\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTotal\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e89\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e100.0\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003cstrong\u003eFigure 2: Seroprevalence of Syphilis among Donors\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eFigure 2 shows the overall seroprevalence of syphilis, with only 2.25% of donors testing positive for anti-Treponema pallidum antibodies.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.3. Statistical Analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eKey statistical measures are presented in Table 3.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3: Statistical Measures of Syphilis Seroprevalence\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"387\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eStatistical Measure\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eValue\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePrevalence\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e2.25% (2/89)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eOdds Ratio\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e0.02\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eRelative Risk\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e0.04\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e95% Confidence Interval\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e0.01 - 0.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eP-value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e\u0026lt;0.0001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eThis study provides the first seroprevalence estimate of syphilis among blood donors in Merowe, Northern Sudan. The observed prevalence of 2.25% is lower than rates reported from other Sudanese regions\u0026mdash;such as 13% in North Darfur [12] and 3.7% in Khartoum [11]\u0026mdash;yet remains higher than the global average of approximately 0.5% [20].\u003c/p\u003e\n\u003cp\u003eGeographical variation may reflect differences in sexual health awareness, accessibility of health services, cultural norms, or effectiveness of donor screening programs. The relatively low prevalence in Merowe could be influenced by recent demographic shifts post-dam construction, potentially altering local transmission dynamics.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eComparative Analysis: Regional and Global Context\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;Figure 3 illustrates how Merowe\u0026rsquo;s prevalence situates within regional and global contexts:\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFigure 3: Comparative Syphilis Seroprevalence across Regions (%)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eFigure 3 provides a visual comparison of syphilis seroprevalence rates across different regions, contextualizing the Merowe finding within broader epidemiological patterns.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe lower prevalence in Merowe compared to other high-burden regions in Sudan suggests potential success in local health interventions or unique socio-demographic buffers. Nevertheless, the rate exceeding the global average underscores the continued relevance of syphilis screening in Sudanese blood banks.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStrengths and Limitations\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;Strengths include the use of standardized ELISA testing and ethical compliance. Limitations are the small sample size, exclusive male cohort, cross-sectional design, and lack of confirmatory testing (e.g., TPHA) to differentiate active from past infection.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePublic Health Implications\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;These findings:\u003c/p\u003e\n\u003col\u003e\n \u003cli\u003eProvide a baseline for future surveillance in Northern State.\u003c/li\u003e\n \u003cli\u003eSupport the necessity of sustained mandatory syphilis screening.\u003c/li\u003e\n \u003cli\u003eHighlight opportunities for integrated donor education on sexual health.\u003c/li\u003e\n \u003cli\u003eEmphasize the value of decentralized data in shaping national blood safety policies.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"5. Conclusion","content":"\u003cp\u003eThis first epidemiological assessment from Merowe, Northern Sudan, documents a syphilis seroprevalence of 2.25% among asymptomatic male blood donors. Although lower than other Sudanese regions, the rate remains above global averages, justifying continued screening. The study fills a critical data gap and offers a benchmark for monitoring trends, evaluating interventions, and informing evidence-based blood safety strategies in similar transitional settings.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate:\u003c/strong\u003e Approved by Abdulatif Alhamed University of Technology. Written informed consent was obtained from all participants.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication:\u003c/strong\u003e Not applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials:\u003c/strong\u003e Available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests:\u003c/strong\u003e The authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e This research received no external funding.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors' contributions:\u0026nbsp;\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;D.A.A.: Conceptualization, Methodology, Investigation, Formal Analysis, And Writing \u0026nbsp;Original Draft.\u003cbr\u003e\u0026nbsp;S.A.I.: Investigation, Validation, Writing – Review \u0026amp; Editing.\u003cbr\u003e\u0026nbsp;H.E.S.: Investigation, Resources, Writing – Review \u0026amp; Editing.\u003cbr\u003e\u0026nbsp;H.A.A.: Conceptualization, Supervision, Project Administration, Writing – Review \u0026amp; Editing.\u003cbr\u003e\u0026nbsp;All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements:\u003c/strong\u003e We thank the staff of Merowe Blood Donation Center and Abdulatif Alhamed University of Technology for their support.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eGrenache A, et al. A population-based longitudinal study on demographic changes and blood demand. Blood Adv. 2017;1(14):867\u0026ndash;74.\u003c/li\u003e\n \u003cli\u003eYu C, et al. Institutional incentives for altruism: gifting blood in China. BMC Public Health. 2013;13:524.\u003c/li\u003e\n \u003cli\u003ePlafond RE, Luke hart SA. Biological basis for syphilis. Clin Microbiol Rev. 2006;19(1):29\u0026ndash;49.\u003c/li\u003e\n \u003cli\u003eBrigitte C, et al. Interaction of Treponema pallidum with human platelets. PLoS One. 2019;14(1):e0210902.\u003c/li\u003e\n \u003cli\u003eKatz LM, et al. Transfusion-transmitted syphilis: still a risk? Transfusion. 2019;59(11):3263\u0026ndash;6.\u003c/li\u003e\n \u003cli\u003eKitchen AD, Barbara JA. Syphilis and blood donation: is there a risk? Transfus Med. 2018;28(3):243\u0026ndash;51.\u003c/li\u003e\n \u003cli\u003eRolfs RT. Treatment of syphilis. Clin Infect Dis. 1995;20(Suppl 1):S23\u0026ndash;38.\u003c/li\u003e\n \u003cli\u003eKitayama K, et al. Syphilis in the Americas: a systematic review protocol. Syst Rev. 2017;6(1):195.\u003c/li\u003e\n \u003cli\u003eFederal Ministry of Health. National HIV and syphilis sero-behavioral survey in Sudan. Khartoum; 2018.\u003c/li\u003e\n \u003cli\u003eRahlenbeck SI, et al. Infection with HIV, syphilis and HBV in Ethiopia. Int J STD AIDS. 1997;8:261\u0026ndash;4.\u003c/li\u003e\n \u003cli\u003eElsheikh SM, et al. Sero-prevalence of TTIs at Central Blood Bank, Khartoum. Afr J Lab Med. 2020;9(1):987.\u003c/li\u003e\n \u003cli\u003eAdam NK, et al. Seroprevalence of syphilis among donors in North Darfur. J Microbiol Exp. 2021;9(2):42\u0026ndash;5.\u003c/li\u003e\n \u003cli\u003eRahlenbeck SI, et al. (as above).\u003c/li\u003e\n \u003cli\u003eQuintas E. Prevalence of syphilis in blood donors in Angola, 2011\u0026ndash;2016. Clin Med Rep. 2018;2(1):1\u0026ndash;4.\u003c/li\u003e\n \u003cli\u003eMavenyengwa RT, et al. Prevalence of HIV, syphilis, HBV, HCV in Namibian donors. BMC Public Health. 2014;14:424.\u003c/li\u003e\n \u003cli\u003eSiraj N, et al. Seroprevalence of TTIs in Eritrea. BMC Infect Dis. 2018;18(1):264.\u003c/li\u003e\n \u003cli\u003eOlokoba AB, et al. Syphilis in voluntary donors in Nigeria. Eur J Sci Res. 2009;31(3):335\u0026ndash;8.\u003c/li\u003e\n \u003cli\u003eElyamany G, et al. Syphilis prevalence among donors in Saudi Arabia. Electron Physician. 2016;8(8):2747\u0026ndash;51.\u003c/li\u003e\n \u003cli\u003eChaudhary V, et al. Seroprevalence of TTIs in Uttar Pradesh. Int J Med Sci Public Health. 2014;3(11):1381\u0026ndash;4.\u003c/li\u003e\n \u003cli\u003eNewman L, et al. Global estimates of STI prevalence and incidence. PLoS One. 2015;10:e0143304.\u003c/li\u003e\n\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":"Syphilis, Treponema pallidum, blood donors, seroprevalence, transfusion-transmissible infections, Sudan, Northern State, ELISA","lastPublishedDoi":"10.21203/rs.3.rs-8787035/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8787035/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground:\u003c/strong\u003e Syphilis remains a significant transfusion-transmissible infection, yet regional epidemiological data in Sudan is sparse. The Northern State, particularly Merowe, lacks prior seroprevalence studies despite significant demographic shifts following the Merowe Dam construction. This study aimed to establish the first baseline syphilis prevalence among asymptomatic blood donors in this underrepresented region.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods:\u003c/strong\u003e A cross-sectional study was conducted in January 2022 at the Merowe blood donation center. Eighty-nine consecutive asymptomatic male blood donors were screened for anti-Treponema pallidum antibodies using a commercial Enzyme-Linked Immunosorbent Assay (ELISA) kit. Demographic and clinical data were collected via structured questionnaire.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e The overall seroprevalence was 2.25% (2/89). The donor population median age was 32 years (range: 18–64). Statistical analysis yielded an odds ratio of 0.02, relative risk of 0.04, 95% confidence interval 0.01–0.1, and p-value \u0026lt;0.0001.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion:\u003c/strong\u003e This is the first syphilis seroprevalence report from Merowe, revealing a lower rate compared to other Sudanese regions but higher than the global average. The findings fill a critical geographical data gap, support evidence-based blood safety strategies, and underscore the need for localized surveillance in demographically dynamic regions.\u003c/p\u003e","manuscriptTitle":"First Epidemiological Assessment: Syphilis Seroprevalence among Asymptomatic Blood Donors in Merowe, Northern Sudan, 2022","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-05 12:45:32","doi":"10.21203/rs.3.rs-8787035/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":"938d514e-8f44-49c4-bdb3-852a30259096","owner":[],"postedDate":"February 5th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":62316186,"name":"Pathology"}],"tags":[],"updatedAt":"2026-02-05T12:45:32+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-05 12:45:32","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8787035","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8787035","identity":"rs-8787035","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}