Prevalence of antibodies against equine influenza virus in sport horses from Argentina during 2015 and 2016

Abstract

The population of sport equines of Argentina frequently transported was analyzed through a two-stage sampling. In this population vaccination against equine influenza is mandatory. Antibodies against two strains of equine influenza virus (A/eq/2La Plata 93 and A/eq/Argentina/E2345-1/2012) were evaluated through the hemagglutination inhibition technique. Based on the titer obtained, horses were classified as protected, partially protected and not protected. Fifty-seven per cent and 59 % of the horses were not protected against La Plata 93 and Argentina 2012 strains, respectively. Thirty-four per cent of the horses were partially protected against La Plata 93 and Argentina 2012 strains, respectively. Finally, 9 % and 8 % of the animals were protected against La Plata 93 and Argentina 2012 strains, respectively. Older animals with more vaccinations and with the last vaccination applied closer to the date of sampling had higher antibody levels. Less than 10 % of the horses had protective titer and a high percentage had insufficient titer to avoid the disease, suggesting that in Argentina a large number of horses can spread the disease without showing clinical signs.