Climatic factors associated with the prevalence of bluetongue virus infection of cattle herds in Queensland, Australia.

The prevalence of bluetongue virus in 410 cattle herds in Queensland, Australia, was estimated by using the bluetongue virus agar gel immunodiffusion test, and 18 climatic variables were estimated for the location of each herd. Temperature and rainfall were the factors most closely associated with the prevalence of bluetongue virus in the herds, and the simplest relationship which explained the most variability in the prevalence included the average daily maximum temperature and the average annual rainfall. This relationship accounted for nearly 40 per cent of the variability in herd prevalence. The generally poor association between climatic factors and herd prevalence indicates that other factors need to be included in any model of the epidemiology of bluetongue virus.