Long-term persistence of neutralising antibodies against bluetongue virus serotype 8 in naturally infected cattle.

Neutralising antibodies to bluetongue virus (BTV) in convalescent cattle have been described as persistent. Controlled laboratory studies, however, rarely last longer than a couple of weeks and long-term field data are lacking. This study followed twelve cattle that had been naturally infected with bluetongue virus serotype 8 (BTV-8) in Germany in 2006. Using ELISAs and a serum neutralisation test, we found a strong humoral immune response four to six years after the last exposure to BTV-8; based on data from long-term vaccine studies, it is highly likely that this coincides with immunity to reinfection with the same serotype.