How do foals typically contract equine herpes virus?

Foals typically contract equine herpes virus (EHV) primarily from their mother. This is because the virus can be transmitted in utero or shortly after birth through direct contact or through the maternal milk. Foals are particularly vulnerable to EHV because their immune systems are still developing, making them more susceptible to infections. During the perinatal period, if the mare is shedding the virus, there's a high chance that the foal will be exposed to it directly.

In contrast, while contaminated feed, other environmental factors, or even vaccinations may play roles in the context of infectious disease management, they are not the primary modes of EHV transmission in foals. Contaminated feed would mainly be associated with other types of infections, certain vaccines are designed to prevent diseases rather than transmit them, and environmental exposure generally involves a more indirect route of transmission that is not specific to foals contracting EHV directly from maternal sources. Thus, the primary route of infection in foals is through their mothers.