Cross-sectional study of bluetongue virus serotype 8 infection in South American camelids in Germany (2008/2009)

Bluetongue (BT) is a major disease of ruminant livestock that can have a substantial impact on income and animal welfare. In South American camelids (SAC), fatalities related to bluetongue virus (BTV) infection were reported in Germany and France during the recent BTV-8 and BTV-1 epizootics, which raised concern about the role of SAC in the epidemiology of BTV. Therefore, a large-scale serological and virological study was conducted in Germany from autumn 2008 to spring 2009. Risk factors associated with BTV infection were analysed by multiple logistic regression. These included age, species, gender and housing arrangements of SAC as well as the location of the herds and the presence of ruminants on farms. Altogether, 249 (14.3%) of 1742 SAC were found seropositive by BTV ELISA, and 43 (47.3%) of the 91 herds had at least one BTV-seropositive SAC. However, no BTV RNA was detected in any of the seropositive samples. Seroprevalence depended on the sampling region and probably on age, but not on any other analysed risk factors associated with BTV infection in ruminants. The highest seroprevalence was found in the west of Germany where the BTV-8 epizootic started in 2006. Recorded BTV-8 related disease and fatalities are discussed. Although the prevalence of BTV-8 antibodies was high in some regions, the virological results indicate that SAC play a negligible role in the epidemiology of this virus infection.