Equine Infectious Anemia (EIA) not always traceable with bloodtest

Up until now, it was believed that the EIA (Equine Infectious Anemia)-virus could always be found with a simple blood test. However, a recent study in Argentina found that horses can be infected with the virus for up to two years before the bloodtest turns out positive.

After a horse is diagnosed with EIA, there is only one 'treatment': The horse has to be put down immediately. EIA spreads really fast to other horses, and so putting the horse down is the only option. This decision is always made after a positive blood test. But a recent study in Argentina discovered that those blood tests are not that reliable, because some horses had been infected with EIA for almost two years before they tested positive.

This study was started after some horses tested positive for EIA, even though they had never been in contact with other infected horses. So as it turns out, there is a silent virus of EIA. Still, there is no need to panic. It is not clear yet how big this group of silent carriers is, so focus remains on the horses that do test positive. The current testing methods are certainly reliable enough, so the study states.