Monkeypox virus causes monkeypox in both humans and animals. It was first found in 1958 in macaque monkeys that were being used as laboratory animals. The monkeys are often used for neurological experiments. The virus is typically found in rainforest regions of central and West Africa.

It was first discovered in 1970 in humans and from 1970 to 1986 there were over 400 cases reported in humans. The main infection route was through contact with infected animals and their bodily fluids.
The first outbreak in the US was in 2003 in Illinois, Indiana, and Wisconsin. Pet prairie dogs imported from Africa were the cause of the outbreak. The virus can spread from both animals to human and human to human. From human to human the virus spreads through their breath and through contact with an infected person’s bodily fluids. Animal to human transmission is more common. The virus then incubates in the host for 10-14 days and causes symptoms that include swelling of the lymph nodes, muscle pain, headache, fever, and sometimes rash.