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Veterinary microbiology2025; 306; 110548; doi: 10.1016/j.vetmic.2025.110548

Equine infectious anemia virus worldwide prevalence: A 24-year retrospective review of a global equine health concern with far-reaching implications.

Abstract: Equine Infectious Anemia Virus (EIAV), the causative agent of Equine Infectious Anemia (EIA), presents a significant threat to equine populations worldwide. While local EIAV prevalence has been estimated in several studies, no global prevalence has been determined. Thus, this study aimed to review the literature on EIAV prevalence in the 21st century. A comprehensive electronic search was conducted in PubMed, Web of Science, Scopus, Google Scholar, SciELO.org, African Journals Online, and NZresearch.org, yielding 105 articles published between January 1st, 2000, and December 31st, 2024 (spanning 24 years). EIAV prevalence was estimated in 42 countries and is particularly high in Mexico (North America; 27.14 % [95 % CI, 25.11 - 29.17]) and Guatemala (Central America; 15.9 % [95 % CI, 9.66 - 22.14]). While EIAV prevalence in the United States of America (USA) remains low and stable over time, the relatively elevated prevalence in the Southern states, along with their extensive border with Mexico, places these areas at a higher risk. EIAV prevalence estimated per province/state in the USA, Argentina, and Brazil, indicated higher rates in humid and warmer regions. EIAV has a low presence in the Middle East, while the scarcity of epidemiological studies in Africa and Oceania complicates the estimation of EIAV prevalence in these regions. These findings highlight the need for continued intensive surveillance in both high-risk regions and areas lacking data. Given that insect vectors are the primary natural transmission route, global warming may lead to increased vector movement into temperate areas, potentially contributing to a surge in EIAV infections.
Publication Date: 2025-05-08 PubMed ID: 40359782DOI: 10.1016/j.vetmic.2025.110548Google Scholar: Lookup
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Summary

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Equine Infectious Anemia Virus (EIAV) is a global health concern affecting horses, with variable prevalence in different regions over the last 24 years. This study comprehensively reviews the worldwide distribution and prevalence of EIAV to identify high-risk areas and gaps in epidemiological data.

Study Objective and Background

  • The study aims to determine the global prevalence of Equine Infectious Anemia Virus (EIAV) from 2000 to 2024.
  • EIAV causes Equine Infectious Anemia (EIA), a serious disease threatening horse populations globally.
  • Previous data mostly focused on local prevalence, lacking a comprehensive worldwide overview.

Methodology

  • A systematic electronic literature search was performed across major databases: PubMed, Web of Science, Scopus, Google Scholar, SciELO.org, African Journals Online, and NZresearch.org.
  • Data from 105 relevant articles published between January 1, 2000, and December 31, 2024, were included.
  • Prevalence data were extracted and analyzed from 42 countries representing different continents and climates.

Key Findings

  • High Prevalence Regions:
    • Mexico shows the highest prevalence with 27.14% (95% CI: 25.11–29.17).
    • Guatemala also has a significantly high prevalence of 15.9% (95% CI: 9.66–22.14).
  • United States:
    • Overall low and stable prevalence.
    • Southern states have relatively higher prevalence rates, likely influenced by proximity to Mexico and their warmer, humid climates.
  • Other Countries:
    • Argentina and Brazil show regional differences, with warmer and more humid provinces/states exhibiting higher EIAV rates.
    • The Middle East shows low EIAV prevalence.
    • Data scarcity in Africa and Oceania creates challenges in accurately estimating prevalence there.

Implications and Recommendations

  • Surveillance: Continuous and improved epidemiological surveillance is necessary, particularly in identified high-prevalence regions and where data are currently inadequate.
  • Environmental Considerations:
    • Insect vectors (such as horseflies) are the main natural transmitters of EIAV.
    • Climate change and global warming may expand the geographic range and activity of these vectors, increasing the risk of EIAV spreading into currently unaffected temperate zones.
  • Risk Management: Border regions and countries with humid and warm climates should prioritize preventive measures to control vector populations and reduce transmission rates.

Significance of the Study

  • This is the first comprehensive, multi-decade global review of EIAV prevalence consolidating data from diverse regions.
  • It offers critical insights into global health threats to equine populations and highlights the effects of environmental and geographic factors on disease prevalence.
  • The study underscores a potential increase in EIAV risk due to climate change, emphasizing a need for proactive measures.

Cite This Article

APA
Thieulent CJ, Carossino M, Reis JKPD, Vissani MA, Barrandeguy ME, Valle-Casuso JC, Balasuriya UBR. (2025). Equine infectious anemia virus worldwide prevalence: A 24-year retrospective review of a global equine health concern with far-reaching implications. Vet Microbiol, 306, 110548. https://doi.org/10.1016/j.vetmic.2025.110548

Publication

ISSN: 1873-2542
NlmUniqueID: 7705469
Country: Netherlands
Language: English
Volume: 306
Pages: 110548
PII: S0378-1135(25)00183-X

Researcher Affiliations

Thieulent, Côme J
  • Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA. Electronic address: cthieulent@lsu.edu.
Carossino, Mariano
  • Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA; Louisiana Animal Disease Diagnostic Laboratory (LSU Diagnostics), School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA. Electronic address: mcarossino1@lsu.edu.
Reis, Jenner K P D
  • Laboratório de Retroviroses, Departamento de Medicina Veterinária Preventiva, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil. Electronic address: jenner@ufmg.br.
Vissani, Maria A
  • Instituto de Virología, CICVyA, Instituto Nacional de Tecnología Agropecuaria (INTA), Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina; Escuela de Veterinaria, Facultad de Ciencias Agrarias y Veterinarias, Universidad del Salvador, Pilar, Buenos Aires, Argentina. Electronic address: vissani.aldana@inta.gob.ar.
Barrandeguy, Maria E
  • Instituto Nacional de Investigación Agropecuaria (INIA), Plataforma de Investigación en Salud Animal, Estación Experimental La Estanzuela, Colonia, Uruguay. Electronic address: mbarrandeguy@inia.org.uy.
Valle-Casuso, José-Carlos
  • ANSES Animal Health Laboratory, PhEED Unit, Goustranville, France. Electronic address: jose-carlos.valle-casuso@anses.fr.
Balasuriya, Udeni B R
  • Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA. Electronic address: balasuriya1@lsu.edu.

MeSH Terms

  • Animals
  • Equine Infectious Anemia / epidemiology
  • Equine Infectious Anemia / virology
  • Infectious Anemia Virus, Equine / isolation & purification
  • Horses
  • Prevalence
  • Global Health
  • Retrospective Studies

Conflict of Interest Statement

Declaration of Competing Interest The authors declare that they have no competing interests.

Citations

This article has been cited 4 times.
  1. Garzaro D, Rodríguez N, Medina G, Alcazar W, Gualdron M, Siem JA, Sulbaran Y, Barrios M, Liprandi F, Jaspe RC, Pujol FH. Isolation of Madariaga Virus (MADV) in a Horse Coinfected with Equine Infectious Anemia in Venezuela: A Review of MADV Circulation in the Country. Vet Sci 2026 Jan 10;13(1).
    doi: 10.3390/vetsci13010071pubmed: 41600727google scholar: lookup
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    doi: 10.3390/ani15233499pubmed: 41375557google scholar: lookup
  3. Wiernasz N, Deshiere A, Agüero M, Garcia E, de la Haza R, Cáceres G, Touzain F, Blanchard Y, Lecouturier F, Froger D, Berthet N, Hans A, Valle-Casuso JC. Whole genome sequencing and phylogenetic analysis of the equine infectious anemia virus associated with 2017 Spain outbreaks. BMC Vet Res 2025 Dec 4;22(1):10.
    doi: 10.1186/s12917-025-05100-4pubmed: 41340062google scholar: lookup
  4. Liang H, Zhou B, Hu Z, Chu X, Wang X, Du C, Wang X. Development of a Broad-Spectrum Antigen-Capture ELISA Using Combined Anti-p26 Polyclonal and Monoclonal Antibodies for Detection of Equine Infectious Anemia Virus. Microorganisms 2025 Jun 27;13(7).