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Home / Equine Research Bank / BMC Vet Res / Low transmission rates of Equine infectious anemia virus (EI...
BMC veterinary research2022; 18(1); 286; doi: 10.1186/s12917-022-03384-4

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.

Abstract: Marajó Island, within in the Amazon River Delta, supports numerous bands of feral equids including the genetically distinct Marajoara horses. Approximately 40% of the equids on the island are infected with Equine infectious anemia virus (EIAV). This high seropositivity rate coupled with the need to preserve rare breeds such as the Marajoara horse precludes euthanasia as the primary means for controlling EIAV in this region. In the absence of iatrogenic transmission, spread of this lentivirus is mediated primarily by hematophagous insects, whose year-round prevalence on the island is supported by favorable climatic conditions. In addition, cases of vertical EIAV transmission have been observed suggesting inclusion of seropositive mares in restorative breeding programs could result in their progeny becoming infected with this virus either pre-parturition or post-partum via hematophagous insects. Therefore, the aim of this study was to evaluate EIAV vertical and post-partum insect-mediated transmission rates among foals born to seropositive feral mares until natural weaning. Serum samples from foals born to seropositive feral mares within the Soure municipality, of Marajó Island, were collected to investigate their serological status, using an indirect ELISApgp45, with positive samples confirmed using the classical agar gel immunodiffusion (AGID) assay. Results: The serological status of 28 foals were monitored over a 2-year period with some subjects, depending on their date of birth, being sampled up to six times. All foals remained with their respective mares until fully weaned at approximately 10 months of age. Only 2 foals (7.14%) in the study group became seropositive against EIAV. Conclusions: The results demonstrate that in most cases it is possible to obtain seronegative foals born to and eventually weaned by EIA positive mares, even in equatorial regions where substantial rainfall and high temperatures favor the proliferation of insect vectors.
© 2022. The Author(s).
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Publication Date: 2022-07-22 PubMed ID: 35869474PubMed Central: PMC9306203DOI: 10.1186/s12917-022-03384-4Google Scholar: Lookup
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Summary

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The research explored the transmission rates of Equine infectious anemia virus (EIAV) in foals born to infected mares in an Amazon delta region. Despite the favourable climate for insect vectors and high infection rate in the adult equine population, the study found low transmission rates in the newborn foals.

Objective of the Research

  • The aim of this research was to investigate the vertical transmission (from mother to offspring during pregnancy) and post-partum insect-mediated infection rate of EIAV among foals born to seropositive (EIAV- infected) feral mares.

Research Methodology

  • The research was conducted on Marajo Island, home to unique Marajoara horses and a potent EIAV infection rate.
  • In order to mitigate the risk of the spread without resorting to euthanizing infected equines, the researchers explored if seropositive mares could give birth to seronegative foals that remain EIAV-free, even post-weaning.
  • Serum samples from 28 foals born to seropositive mares were collected and their serological status regularly monitored over a two-year period.
  • The indirect ELISApgp45 test was used to analyze the serum samples, with positive results then confirmed using the classical agar gel immunodiffusion (AGID) assay.

Research Findings

  • Contrary to the expected high transmission rates due to favorable climatic conditions for the insect vector, only 2 out of the 28 foals (approximately 7.14%) tested positive for EIAV in the study.
  • All foals remained with their mares until they were fully weaned at around ten months of age.
  • Thus, the research concluded that it is likely for seropositive feral mares to give birth to and successfully wean off seronegative foals even in equatorial regions where climatic conditions are conducive to the proliferation of insect vectors.

Cite This Article

APA
Resende CF, Santos AM, Cook RF, Victor RM, Câmara RJF, Gonçalves GP, Lima JG, Maciel E Silva AG, Leite RC, Dos Reis JKP. (2022). 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, 18(1), 286. https://doi.org/10.1186/s12917-022-03384-4

Publication

BMC veterinary research
ISSN: 1746-6148
NlmUniqueID: 101249759
Country: England
Language: English
Volume: 18
Issue: 1
Pages: 286
PII: 286

Researcher Affiliations

Resende, Cláudia Fideles
  • Laboratório de Retroviroses, Departamento de Medicina Veterinária Preventiva, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil.
Santos, Alison Miranda
  • Faculdade de Medicina Veterinária, Instituto de Medicina Veterinária, Universidade Federal do Pará, Castanhal, Pará, 68740-970, Brazil.
Cook, Richard Frank
  • Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky, 40546-0099, USA.
Victor, Raphael Mattoso
  • Laboratório de Retroviroses, Departamento de Medicina Veterinária Preventiva, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil.
Câmara, Rebeca Jéssica Falcão
  • Laboratório de Retroviroses, Departamento de Medicina Veterinária Preventiva, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil.
Gonçalves, Gilberto Pereira
  • Faculdade de Medicina Veterinária, Instituto de Medicina Veterinária, Universidade Federal do Pará, Castanhal, Pará, 68740-970, Brazil.
Lima, Juliana Gonçalves
  • Faculdade de Medicina Veterinária, Instituto de Medicina Veterinária, Universidade Federal do Pará, Castanhal, Pará, 68740-970, Brazil.
Maciel E Silva, André Guimarães
  • Faculdade de Medicina Veterinária, Instituto de Medicina Veterinária, Universidade Federal do Pará, Castanhal, Pará, 68740-970, Brazil.
Leite, Romulo Cerqueira
  • Laboratório de Retroviroses, Departamento de Medicina Veterinária Preventiva, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil.
Dos Reis, Jenner Karlisson Pimenta
  • Laboratório de Retroviroses, Departamento de Medicina Veterinária Preventiva, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil. jenner@ufmg.br.

MeSH Terms

  • Animals
  • Equine Infectious Anemia / epidemiology
  • Euthanasia, Animal
  • Female
  • Horse Diseases / epidemiology
  • Horses
  • Humans
  • Infectious Anemia Virus, Equine
  • Infectious Disease Transmission, Vertical / veterinary
  • Insect Vectors
  • Parturition
  • Pregnancy

Conflict of Interest Statement

The authors declare no conflict of interest.

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Citations

This article has been cited 4 times.
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