Transmission of Equine Infectious Anemia Virus by Tabanus fuscicostatus

Abstract

SUMMARY The mechanical transmission of equine infectious anemia ( eia ) virus by Tabanus fuscicostatus was investigated. In 1 of 7 transmission trials, a single horsefly transmitted eia virus from an acutely infected pony to a susceptible pony. Groups of horseflies isolated for 3, 10, or 30 minutes before refeeding transmitted eia virus, whereas those isolated for 4 or 24 hours did not. Data from field studies indicate that the home range or flight distance of horseflies may exceed 4 miles. That information together with our observations suggest that segregation of infected horses (usually defined as at least 200 yards from susceptible horses) as a control measure for eia may not be an adequate safeguard against transmission in areas where horseflies are numerous.