Transmissibility and abortogenic effect of equine viral arteritis in mares.

The research focuses on a study of the transmission and abortion-causing effects of equine viral arteritis (EVA) in pregnant mares, concluding that exposure to the virus often results in abortion.

Study Conduct and Observations

• The research was conducted on a group of 14 pregnant mares that were exposed to 4 donor mares that had been bred with stallions infected with equine viral arteritis virus.
• Following exposure to the virus, all the animals showed febrile response, essentially demonstrating feverish conditions. Each of the donor mares and 12 of the pregnant mares showed this response.
• Subsequent testing revealed that all 18 mares became seropositive after exposure, which means they tested positive for the presence of antibodies in their blood serum, indicating an immune response to the EVA virus.
• Interestingly, while the EVA virus was isolated from the nasopharynx of 5 of the pregnant mares, none of the donor mares showed such presence of the virus.

Abortogenic Effects

• Of the 14 pregnant mares, 10 ended up aborting their fetuses. This demonstrates a high abortion rate among the mares that were exposed to the EVA virus.
• EVA virus was isolated from the fetal specimens or placentas of 8 of the aborted mares, confirming that the virus had crossed the placental barrier and infected the fetuses.

Conclusion

• The study reveals the high potential of EVA virus transmissibility in horses. It doesn’t only infect an exposed mare, but has a probability of crossing the placenta (as evident from the virus’s presence in fetal specimens or placenta) and causing foetal infection that may lead to abortion.