Transmission and distribution of African horse sickness virus serotypes in South African zebra

The prevalences of African horse sickness (AHS) virus serotypes in zebra foals from the Kruger National Park, South Africa were examined for possible associations between serotypes. Serotypes known to cross-react were combined for analysis. The distributions of serotypes between zebra were not always independent; in 7-8 month old zebra positive pairwise associations were observed between 3 serotypes. This could be generated by biological interactions between serotypes or heterogeneity in host-vector transmission. The data were also used to estimate the basic reproduction number, R0. For AHS virus overall, estimates of R0 ranged from 31-68. This underlines the need for a better understanding of serotype transmission and interactions in AHS.