Global prevalence and risk factors of equine infectious anemia: A systematic review and meta-analysis.
Abstract: Equine infectious anemia (EIA) is a lentiviral disease affecting members of the Equidae family, with global distribution and significant implications for animal health and biosecurity. Despite numerous individual reports, a comprehensive synthesis of its global prevalence and risk factors remains lacking. This study aimed to conduct a systematic review and meta-analysis to estimate the global prevalence of EIA, identify diagnostic trends, and evaluate factors associated with heterogeneity across studies. Unassigned: A systematic search was conducted in six major databases (PubMed, Scopus, Web of Science, ScienceDirect, Cochrane Library, and ProQuest), yielding 312 records. After Preferred Reporting Items for Systematic Reviews and Meta-Analyses-guided screening, 29 eligible studies published between 1975 and 2024 were included in the study. Meta-analysis was performed using R Studio (version 4.4.2) employing a random-effects model. Subgroup analyses and meta-regression were conducted to explore heterogeneity across host species, continent, diagnostic method, and study period. Publication bias was assessed through funnel plots and Egger's test. Unassigned: The global pooled prevalence of EIA was estimated at 20.97% (95% confidence interval [CI]: 11.08-30.85), with substantial heterogeneity (I = 99.3%). South America reported the highest regional prevalence (27.21%), while horses showed the greatest susceptibility among Equidae (25.40%). Diagnostic methods varied, with agar gel immunodiffusion being the most commonly used (18.62% prevalence detection). A declining trend in prevalence (2.19%-28.70%) was noted from 2015 to 2022. No significant publication bias was detected. Meta-regression revealed that climate and study period partially explained the heterogeneity. Unassigned: This study highlights the substantial global burden and diagnostic variability of EIA, emphasizing the need for enhanced surveillance in endemic areas, standardized diagnostic protocols, and strengthened quarantine practices. Expanding serological monitoring in underrepresented regions and integrating climatic and ecological data into control strategies are vital for mitigating EIA transmission risks.
Copyright: © Firdausy, et al.
Publication Date: 2025-06-06 PubMed ID: 40689174PubMed Central: PMC12269943DOI: 10.14202/vetworld.2025.1440-1451Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
- Review
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
This research is a systematic review and meta-analysis on the global prevalence and risk factors of Equine Infectious Anemia (EIA), a viral disease impacting the Equidae family of animals, such as horses. The study reveals a significant worldwide presence of EIA and underscores the need for better surveillance, standardized diagnostic procedures, and robust quarantine protocols to manage it.
Study Methodology
- The research team carried out a systematic search in six significant databases: PubMed, Scopus, Web of Science, ScienceDirect, Cochrane Library, and ProQuest. They selected 29 studies that met their criteria out of 312 records found.
- These studies were conducted between 1975 and 2024 and were included for data harvesting and analysis.
- A meta-analysis was performed using the R Studio software, specifically the ‘random-effects model’ to handle the diversity in study characteristics.
- They employed subgroup analyses and meta-regression techniques to investigate the variability across different factors such as host species, geographic region, diagnostic methods, and time period of the study.
- Publication bias, which refers to the tendency of researchers to publish only positive or significant results, was also assessed.
Study Findings
- The researchers estimated that the global prevalence of EIA is about 20.97%, though this estimate varied greatly across different regions, species, and diagnostic methods (known as ‘heterogeneity’).
- They found that the highest regional prevalence was in South America (27.21%), and among the Equidae family, horses were the most susceptible (25.40%).
- The most commonly used diagnostic method was agar gel immunodiffusion, which detected a prevalence of 18.62%.
- The researchers observed a downward trend in prevalence from 2015 to 2022 (from 28.70% down to 2.19%).
- No significant publication bias was detected in the studies they analyzed. The meta-regression analysis suggested that climate and the time period of study were factors in the observed heterogeneity.
Implications and Recommendations
- This study underlines the substantial global burden of EIA and the variability in its diagnosis, emphasizing the need for improved disease surveillance in areas where EIA is common (endemic areas).
- Implementing standardized diagnostic protocols and enforcing stricter quarantine practices could help manage the risk of EIA spread.
- It recommends extending serological monitoring (blood tests that detect antibodies against the virus) to regions that are currently underrepresented in the research.
- The inclusion of climate and ecological data in EIA control strategies could help in handling the disease more effectively.
Cite This Article
APA
Firdausy LW, Fikri F, Wicaksono AP, Çalışkan H, Purnama MTE.
(2025).
Global prevalence and risk factors of equine infectious anemia: A systematic review and meta-analysis.
Vet World, 18(6), 1440-1451.
https://doi.org/10.14202/vetworld.2025.1440-1451 Publication
Researcher Affiliations
- Division of Veterinary Medicine, Department of Health and Life Sciences, Faculty of Health, Medicine, and Life Sciences, Universitas Airlangga, Banyuwangi, East Java, 68425, Indonesia.
- Research Group of Animal Biomedical and Conservation, Faculty of Health, Medicine, and Life Sciences, Universitas Airlangga, Banyuwangi, East Java, 68425, Indonesia.
- Division of Veterinary Medicine, Department of Health and Life Sciences, Faculty of Health, Medicine, and Life Sciences, Universitas Airlangga, Banyuwangi, East Java, 68425, Indonesia.
- Research Group of Animal Biomedical and Conservation, Faculty of Health, Medicine, and Life Sciences, Universitas Airlangga, Banyuwangi, East Java, 68425, Indonesia.
- Animal Health Division, Indonesian Horse Veterinarian Association, Surabaya, East Java, 60115, Indonesia.
- Department of Biology, Faculty of Science, Eskisehir Osmangazi University, Eskisehir, 26040, Turkey.
- Division of Veterinary Medicine, Department of Health and Life Sciences, Faculty of Health, Medicine, and Life Sciences, Universitas Airlangga, Banyuwangi, East Java, 68425, Indonesia.
- Research Group of Animal Biomedical and Conservation, Faculty of Health, Medicine, and Life Sciences, Universitas Airlangga, Banyuwangi, East Java, 68425, Indonesia.
- Department of Biology, Graduate School of Natural and Applied Sciences, Eskisehir Osmangazi University, Eskisehir, 26040, Turkey.
Conflict of Interest Statement
The authors declare that they have no competing interests.
References
This article includes 59 references
- Wang X.F, Zhang X, Ma W, Li J, Wang X. Host cell restriction factors of equine infectious anemia virus. Virol. Sin. 2023;38(4):485–496.
- Dorey-Robinson D.L, Locker N, Steinbach F, Choudhury B. Molecular characterization of equine infectious anemia virus strains detected in England in 2010 and 2012. Transbound. Emerg. Dis. 2019;66(6):2311–2317.
- Carvelli A, Nardini R, Carnio A, Ricci I, Rosone F, Sala M, Simeoni S, Maccarone D, Scicluna M.T. Equine infectious anemia:The active surveillance of an entire equid population reduces the occurrence of the infection. Transbound. Emerg. Dis. 2024;2024(1):3439871.
- Wang H.N, Rao D, Fu X.Q, Hu M.M, Dong J.G. Equine infectious anemia virus in China. Oncotarget 2018;9(1):1356.
- Machado G, Corbellini L.G, Frias-De-Diego A, Dieh G.N, Dos Santos D.V, Jara M, De Freitas Costa E. Impact of changes of horse movement regulations on the risks of equine infectious anemia:A risk assessment approach. Prev. Vet. Med. 2021;190:105319.
- Sivkova E, Domatskiy V. Innovative Approaches for ecological monitoring of disease outbreaks carried by horseflies (Diptera, Tabanidae):A systematic review. Bangladesh J. Infect. Dis. 2023;10(2):73–88.
- Malik P, Singha H, Sarkar S. Emerging and Re-emerging Infectious Diseases of Livestock. Germany: Springer; 2017. Equine infectious anemia; pp. 215–235.
- Jara M, Frias-De-Diego A, Machado G. Phylogeography of equine infectious anemia virus. Front. Ecol. Evol. 2020;8:127.
- Page M.J, McKenzie J.E, Bossuyt P.M, Boutron I, Hoffmann T.C, Mulrow C.D, Shamseer L, Tetzlaff J.M, Akl E.A, Brennan S.E, Chou R, Glanville J, Grimshaw J.M, Hróbjartsson A, Lalu M.M, Li T, Loder E.W, Mayo-Wilson E, McDonald S, McGuinness L.A, Stewart L.A, Thomas J, Tricco A.C, Welch V.A, Whiting P, Moher D. The PRISMA 2020 statement:An updated guideline for reporting systematic reviews. BMJ 2021;372(71):n71.
- Bamigboye O, Silva R.D. Prevalence of equine infectious anaemia (swamp fever) in Guyana. Br. Vet. J. 1981;137(5):538.
- Barros M.L, Borges A.M.C, Oliveira De A.C.S, Lacerda W, Souza De A.O, Aguiar D.M. Spatial distribution and risk factors for equine infectious anaemia in the state of Mato Grosso, Brazil. Rev. Sci. Technol. 2018;37(3):971–983.
- Bicout D.J, Carvalho R, Chalvet-Monfray K, Sabatier P. Distribution of equine infectious anemia in horses in the North of Minas Gerais State, Brazil. J. Vet. Diag. Investig. 2006;18(5):479–482.
- Borges A.M, Silva L.G, Nogueira M.F, Oliveira A.C, Segri N.J, Ferreira F, Witter R, Aguiar D.M. Prevalence and risk factors for equine infectious anemia in Poconémunicipality, Northern Brazilian Pantanal. Res. Vet. Sci. 2013;95(1):76–81.
- Caij A.B, Tignon M. Epidemiology and genetic characterization of equine infectious anaemia virus strains isolated in Belgium in 2010. Transbound. Emerg. Dis. 2012;61(5):464–468.
- Cappelli K, Capomaccio S, Cook F.R, Felicetti M, Marenzoni M.L, Coppola G, Supplizi A.V, Coletti M, Passamonti F. Molecular detection, epidemiology, and genetic characterization of novel European field isolates of equine infectious anemia virus. J. Clin. Microbiol. 2011;49(1):27–33.
- Cullinane A, Quinlivan M, Nelly M, Patterson H, Kenna R, Garvey M, Gildea S, Lyons P, Flynn M, Galvin P, Neylon M, Jankowska K. Diagnosis of equine infectious anaemia during the 2006 outbreak in Ireland. Vet. Rec. 2007;161(19):647–652.
- Cursino A.E, Vilela A.P.P, Franco-Luiz A.P.M, De Oliveira J.G, Nogueira M.F, Araújo Júnior J.P, De Agular D.M, Kroon E.G. Equine infectious anemia virus in naturally infected horses from the Brazilian Pantanal. Arch. Virol. 2018;163(9):2385–2394.
- Foil L, Adams W.V. Jr, Issel C.J, Pierce R. Tabanid (Diptera) populations associated with an equine infectious anemia outbreak in an inapparently infected herd of horses. J. Med. Entomol. 1984;21(1):28–30.
- Gaudaire D, Lecouturier F, Poncon N, Morilland E, Laugier C, Zientara S, Hans A. Molecular characterization of equine infectious anaemia virus from a major outbreak in southeastern France. Transbound. Emerg. Dis. 2017;65(1):e7–13.
- Hébert L, Polledo G, Lecouturier F, Giorgi M, Beck C, Lowenski S, Laroucau K, Buscher P, Hans A, Becù T. Serological evidence of equine infectious anaemia, West Nile fever, surra and equine piroplasmosis in a herd of horses in northern Argentina. Vet. Parasitol. Reg. Stud. Rep. 2021;24:100566.
- Higgins S.N, Howden K.J, James C.R, Epp T, Lohmann K.L. A retrospective study of owner-requested testing as surveillance for equine infectious anemia in Canada (2009–2012). Can. Vet. J. 2017;58(12):1294–1300.
- Issel C.J, Adams W.V. Jr. Prospective study of progeny of inapparent equine carriers of equine infectious anemia virus. Am. J. Vet. Res. 1985;46(5):1114–1116.
- More S.J, Aznar I, Myers T, Leadon D.P, Clegg T.A. An outbreak of equine infectious anaemia in Ireland during 2006:The modes of transmission and spread in the Kildare cluster. Equine Vet. J. 2008;40(7):709–711.
- More S.J, Aznar I, Bailey D.C, Larkin J.F, Leadon D.P, Lenihan P, Flaherty B, Fogarty U, Brangan P. An outbreak of equine infectious anaemia in Ireland during 2006:Investigation methodology, initial source of infection, diagnosis and clinical presentation, modes of transmission and spread in the Meath cluster. Equine Vet. J. 2008;40(7):706–708.
- Motie A. An outbreak of suspected equine infectious anaemia in Guyana. Br. Vet. J. 1986;142(1):36–40.
- Oliveira F.G, Cook R.F, Naves J.H, Oliveira C.H, Diniz R.S, Freitas F.J, Lima J.M, Sakamoto S.M, Leite R.C, Issei C.J, Reis J.K. Equine infectious anemia prevalence in feral donkeys from Northeast Brazil. Prev. Vet. Med. 2017;140:30–37.
- De Pádua B.R, Dias R.A, Fioravanti M.C.S, Borsanelli A.C. Seroprevalence and risk factors associated with equine infectious anemia in the state of Goiás, Brazil. Prev. Vet. Med. 2022;209:105781.
- Quinlivan M, Cook R.F, Cullinane A. Real-time quantitative RT-PCR and PCR assays for a novel European field isolate of equine infectious anaemia virus based on sequence determination of the gag gene. Vet. Rec. 2007;160(18):611–618.
- Resende C.F, Santos A.M, Cook R.F, Victor R.M, Câmara R.J.F, Gonçalves G.P, Lima J.G, Silva A.G.M, Leite R.C, Dos Reis J.K.P. Low transmission rates of Equine infectious anemia virus (EIAV) in foals born to seropositive feral mares inhabiting the Amazon delta region despite climatic conditions supporting high insect vector populations. BMC Vet. Res. 2022;18(1):286.
- Sharav T, Konnai S, Ochirkhuu N, Ochir T.S, Mekata H, Sakoda Y, Umemura T, Murata S, Chultemdorj T, Ohashi K. Detection and molecular characterization of equine infectious anemia virus in Mongolian horses. J. Vet. Med. Sci. 2017;79(11):1884–1888.
- Thomas R.J. Investigation of equine infectious anaemia in Queensland using gel diffusion. Aust. Vet. J. 1975;51(9):440–442.
- Ataseven V.S, Arslan H.H. Equine infectious anemia in mules, donkeys, and horses:Epidemiologic studies in the different geographic regions of Turkey. J. Equine Vet. Sci. 2005;25(10):439–441.
- Bolfa P, Jeon I, Loftis A, Leslie T, Marchi S, Sithole F, Beck C, Lecollinet S, Zientara S, Hans A, Issel C.J. Detection of West Nile Virus and other common equine viruses in three locations from the Leeward Islands, West Indies. Acta Trop. 2017;174:24–28.
- Cruz F, Fores P, Ireland J, Moreno M.A, Newton R. Freedom from equine infectious anaemia virus infection in Spanish Purebred horses. Vet. Rec. Open. 2015;2(1):e000074.
- Hedger R.S, Barnett I.T, Gray D.F. Some virus diseases of domestic animals in the Sultanate of Oman. Trop. Anim. Health Prod. 1980;12(2):107–114.
- Kasem S, Hashim O, Alkarar A, Hodhod A, Elias A, Abdallah M, Al-Sahaf A, Al-Doweriej A, Qasim I, Abdel-Moneim A.S. Serological cross-sectional survey of equine infectious anemia in Saudi Arabia. Polish J. Vet. Sci. 2022;25(3):365–368.
- Talafha A.Q, Abutarbush S.M, Rutley D.L. Epidemiologic status of equine viral arteritis, equine infectious anemia, and glanders in Jordan. J. Equine Vet. Sci. 2016;42:52–56.
- Turan N, Yilmaz H, Uysal A, Arslan M. Seronegative findings on the investigations of equine infectious anemia in the Marmara region of Turkey. Turk. J. Vet. Anim. Sci. 2002;26(2):299–302.
- Feng J.L. Equine Infectious Anaemia and Its Controlling in China. The Chinese Ministry of Agriculture, Beijing. 1997:4–10.
- Lupulovic D, Savić S, Gaudaire D, Berthet N, Grgić Ž, Matović K, Deshiere A, Hans A. Identification and genetic characterization of equine infectious anemia virus in Western Balkans. BMC Vet. Res. 2021;17(1):168.
- Roberts H. Equine infectious anemia in Europe:An ongoing threat to the UK. Vet. Rec. 2017;181(17):442–446.
- An Q, Li Y, Sun Z, Gao X, Wang H. Spatiotemporal analysis of equine infectious anemia and prediction of risk areas in Europe. Prev. Vet. Med. 2024;230:106281.
- Câmara R.J.F, Bueno B.L, Resende C.F, Balasuriya U.B, Sakamoto S.M, Reis J.K.P.D. Viral diseases that affect donkeys and mules. Animals (Basel) 2020;10(12):2203.
- Malik P, Singha H, Goyal S.K, Khurana S.K, Kumar R, Virmani N, Shanmugasundaram K, Pandey S.B, Kant R, Singh B.K, Singh R.K. Sero-surveillance of equine infectious anemia virus in equines in India during more than a decade (1999–2012). Indian J. Virol. 2013;24(3):386–390.
- Da Costa M.V, Rodrigues G.D, De Lima H.I.L, Krolow T.K, Krüger R.F. Tabanidae (Diptera) captured on horses in the Cerrado biome of Tocantins, Brazil. Res. Sq. 2023;1(9):1–16.
- Cursino A.E, Lima M.T, Nogueira M.F, De Aguiar D.M, Franco Luiz A.P.M, Alves P.A, Araujo Junior J.P, Kroon E.G. Identification of large genetic variations in the equine infectious anemia virus tat-gag genomic region. Transbound. Emerg. Dis. 2021;68(6):3424–3432.
- Abdellah M.C, Karima B, Anes D, Yassine B, Djamel K, Khatima A.O. Contribution to a study on the seroprevalence of Equine Infectious Anemia in Tiaret Province, Northwestern Algeria. Braz. J. Anim. Environ. Res. 2024;7(4):e73766.
- Machado R.D.C, Jardim J.C.D.S, Traesel C.K, Finger P.F, Rodrigues R.O, Brum M.C.S. Epidemiological characteristics and risk factors in focal properties of equine infectious anemia in Rio Grande do Sul State, Brazil. Ciên. Anim. Braz. 2024;25(10):78756E.
- Araújo J.M.D, Costa J.N, Ferrao I.D.S, Ribas J.R.L, Nunes B.Q, Torres P.E, Mendonça A.P.A. Prevalence and main risk factors of equine infectious anemia in the southern of Bahia coast identity Territory, Brazil. Arq. Ins. Biol. 2023;90(1):e00052023.
- Espasandin A.G, Cipolini M.F, Forletti A, Díaz S, Soto J, Martínez D.E, Storani C.A, Monzón N.M, Beltrame J.I, Lucchesi E, Soto P. Comparison of serological techniques for the diagnosis of equine infectious Anemia in an endemic area of Argentina. J. Virol. Methods. 2021;291(5):114101.
- Domínguez M.C.R, Montes-de-Oca-Jiménez R, Chagoyan J.C.V, Pliego A.B, Guerrero J.A.V, González L.I.C, Bernabé S.L. Evaluation of equine infectious anemia virus by the indirect enzyme-linked immunosorbent assay EIA-LAB as screening tools in Mexico. J. Equine Vet. Sci. 2021;98(1):103372.
- De Souza Bezerra C, Dos Anjos D.M, Falcão B.M.R, Bezerra C.W.C, De Andrade Moraes D, Nogueira D.B, Silva M.L.C.R, Alves C.J, Santos C.D.A.B, De Azevedo S.S. True prevalence and spatial distribution of equine infectious Anemia Virus (EIAV) in horses from Northeast Region of Brazil. Acta Sci. Vet. 2021;49:1825.
- Nardini R, Autorino G.L, Issel C.J, Cook R.F, Ricci I, Frontoso R, Rosone F, Scicluna M.T. Evaluation of six serological ELISA kits available in Italy as screening tests for equine infectious anaemia surveillance. BMC Vet. Res. 2017;13(1):105.
- Russi R.C, Garcia L, Cámara M.S, Soutullo A.R. Validation of an indirect in-house ELISA using synthetic peptides to detect antibodies anti-gp90 and gp45 of the equine infectious anaemia virus. Equine Vet. J. 2023;55(1):111–121.
- Villa-Mancera A, Villegas-Bello L, Campos-García H, Ortega-Vargas S, Cruz-Aviña J, Patricio-Martínez F, Olivares-Pérez J, Utrera-Quintana F. Prevalence of equine infectious anemia virus in horses and donkeys determined by comparison of ELISA and AGID in Mexico. Arq. Braz. Med. Vet. Zootec. 2024;76(2):180–186.
- Hu Z, Guo K, Du C, Sun J, Naletoski I, Chu X, Lin Y, Wang X, Barrandeguy M, Samuel M, Wang W, Lau P.I, Wernery U, Raghavan R, Wang X. Development and evaluation of a blocking ELISA for serological diagnosis of equine infectious anemia. Appl. Microbiol. Biotechnol. 2023;107(10):3305–3317.
- Zhang Z, Guo K, Chu X, Liu M, Du C, Hu Z, Wang X. Development and evaluation of a test strip for the rapid detection of antibody against equine infectious anemia virus. Appl. Microbiol. Biotechnol. 2024;108(1):85.
- Wang Y, Ma G, Wang X.F, Na L, Guo X, Zhang J, Liu C, Du C, Qi T, Lin Y, Wang X. Keap1 recognizes EIAV early accessory protein Rev to promote antiviral defense. PLoS Pathogens 2022;18(2):e1009986.
- Lin Y, Wang Y, Li H, Liu T, Zhang J, Guo X, Guo W, Wang Y, Liu X, Huang S, Liao H, Wang X. A platform for the rapid screening of equine immunoglobins F (ab)2 derived from single equine memory B cells able to cross-neutralize to influenza virus. Emerg. Microbes Infect. 2024;13(1):2396864.
Citations
This article has been cited 0 times.Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists