Six years ago in the Big Horn Basin in Wyoming, there was an outbreak of Epizootic Hemorrhagic Disease (EHD) that significantly reduced the white-tailed deer population. Authorities suspect that the disease may be back. It is an insectborne infectious disease that affects wild ruminants, which include animals such as cattle, goats, sheep, camels, deer, llamas, etc. Ideal summer conditions facilitated the disease outbreak - hot temperatures encourage the deer to concentrate around water sources where a certain species of gnat hangs out. When the deer come to the water source the gnats are able to bite them and infect them with the virus.
Anyways, I thought this was an interesting article because I never consider viruses that infect animals or the associate diseases they cause. If you want to know more, including how the disease progresses, go to the following link: