Feeding habits and flight range of blow-flies (Chrysomyia spp.) in relation to anthrax transmission in the Kruger National Park, South Africa.

Carrion-frequenting blow-flies (Chrysomyia albiceps and C. marginalis) were allowed 4 days of feeding on 32P-orthophosphate-labelled blood or an impala carcass (Aepyceros melampus) in the northern Kruger National Park, South Africa. The dispersal and density of fly faecal and discard droplets were then established using a Geiger-Counter, indicating that most droplets occurred between a height of 1 and 3 m on nearby leaves and twigs. This coincides with the preferred feeding height of kudu (Tragelaphus strepsiceros). During a previous anthrax epizootic kudu comprised 73.15% of a total medium to large mammal mortality figure of 1054. Further analysis of mortality shows browsers to have been most severely affected, and it is suggested that this is correlated with feeding habits of these animals. Trapping also yielded radioactively labelled C. albiceps up to 32.5 km and C. marginalis up to 25 km from the isotope source.