Arenavirus is a virus normally found in West Africa and South America.

Arenavirus is transmitted from rats to human, though it is very rare for it to do so. The first known cases of it doing so in the United States were in California during the latter half of 1999 and early 2000.

When infecting humans, [symptoms include high fever, internal bleeding, fluid build-up in the lungs and sometimes death. It is not believed the disease is communicable. The Machupo strain of the virus is the most deadly with a death rate of 60% due to Brazilian hemorrhagic fever. The best known strain, the Lassa, kill approximately 16% of those infected.

Variants of the arenavirus have been successfully treated in the tropics with Ribavirinhas, an antiviral agent.

information gleamed from SacBee (the Sacramento Bee)