Rift Valley fever is a viral zoonotic disease that mainly infects animals, but can also infect humans.  Transmission of the disease occurs via mosquito bites. The disease is most severe in animals, where it has  high mortality rates (~70 - 100%) in newborn ruminants, especially sheep and goats, and abortion in pregnant animals. Other pathologies in animals include fatal hemorrhagic fever, fetal malformation, encephalitis, ocular disease and hepatitis. In humans, the disease is normally mild. In rare cases, the disease is severe, causing neurological disorders, partial or complete blindness, hemorrhagic fever, or thrombosis. No human-to-human contact has been reported.