Answer from Arjun Srivathsa, Centre for Wildlife Studies, Bangalore:
Disease ecology has not been adequately examined in dholes. There are studies that have documented mange and sacrocystis (non-lethal) in dholes. But these are unlikely to be threatening their populations. Although it is possible that CDV or CPV are affecting dhole populations, the major threat currently is still loss of forest habitat and decline in populations of their primary prey species (ungulate herbivores).