Viruses are not important causes of clinical disease of rabbits
in the USA but include the infectious fibromas, papillomatosis,
rabbitpox, myxomatosis, and a herpesvirus infection (Virus III).
Rotaviral enteritis also has been diagnosed in the USA and seems
to contribute to the overall problem of intestinal disease in
rabbits. Viral hemorrhagic disease is found in almost every
country that raises rabbits except the USA. In April 2000, USDA
diagnosed rabbit calicivirus in a backyard facility in Iowa.
Rapid response and cooperation between federal and state
agencies contained this outbreak and eliminated the source of
infection. The USA is currently considered free of rabbit
hemorrhagic disease. Myxomatosis is a fatal disease of all
breeds of domesticated rabbits caused by myxoma virus, a member
of the poxvirus group. Myxomatosis is called “big head” and is
characterized by mucinous skin lesions or myxomas. Wild rabbits
such as the cottontail (Sylvilagus) and jackrabbits (Lepus) are
quite resistant. Myxoma viru