[Serological and clinical proof of freedom from Equine Infectious Anemia (EIA) in imported and domestic horses in Switzerland].

Since 1991, no cases of Equine Infectious Anemia (EIA) have been reported in Switzerland. Risk factors for introduction of the virus into Switzerland are still present or have even increased as frequent inapparent infections, large numbers of imported horses, (since 2003) absence of compulsory testing prior to importation, EIA cases in surrounding Europe, possible illegal importation of horses, frequent short-term stays, poor knowledge of the disease among horse owners and even veterinarians. The aim of this study was to provide evidence of freedom from EIA in imported and domestic horses in Switzerland. The serum samples from 434 horses imported since 2003 as well as from 232 domestic horses fifteen years of age or older (since older horses have naturally had a longer time of being exposed to the risk of infection) were analysed using a commercially available ELISA test. All samples were seronegative, indicating that the maximum possible prevalence that could have been missed with this sample was 0.5% (95% confidence).