The virus can be transmitted from an infected equine to a “clean” equine by biting flies, the use of unsterilized or contaminated medical instruments, or through a blood transfusion. This disease does not affect humans. KDA has identified a prescribed surveillance area within one-half mile of the affected premises, and is working with local officials and horse owners to identify any other horses that may have been within that surveillance area in order to test those animals.
The surveillance area is identified based on risk associated with the potential transfer of the disease. EIA is mechanically transmitted via the mouth parts of biting flies, and research has shown that the EIA virus survives for a limited time on the mouth parts of the fly vectors, so the area of possible exposure is limited to a relatively small radius around the affected premises. Symptomatic horses, those showing clinical signs, are more likely to transmit the disease compared to those that have an in apparent infection. It is estimated after visiting an asymptomatic carrier, only one out of every 6 million flies is likely to become a vector.