Ross River fever is a mosquito-borne disease caused by infection with the Ross River virus. The illness is typically characterised by flu like symptoms combined with polyarthritis and a rash. The virus is endemic to mainland Australia and Tasmania, the island of New Guinea, Fiji, Samoa, the Cook Islands, New Caledonia and several other islands in the South Pacific. The illness is Queensland's most prolific mosquito-borne disease.
Symptoms and signs
Symptoms of the disease vary widely in severity, but major indicators are arthralgia, arthritis, fever, and rash.
Epidemiology
Most notifications are from Queensland, tropical Western Australia and the Northern Territory. Geographical risk factors include areas of higher rainfall and higher maximal tides.
History
The first outbreak of RRF was in 1928 in the Hay and Narrandera region in New South Wales, Australia. The virus was first isolated in 1959 from a mosquito trapped along the Ross River in Townsville, Queensland. Since then, outbreaks have occurred in all Australian states, including Tasmania, and metropolitan areas.
Research
The study of RRF has been recently facilitated by the development of a mouse model. Mice infected with RRV develop hind-limb arthritis/arthralgia which is similar to human disease. The disease in mice is characterized by an inflammatory infiltrate including macrophages which are immunopathogenic and exacerbate disease. Furthermore, mice deficient in the C3 protein do not develop severe disease following infection. This indicates that an aberrant innate immune response is responsible for severe disease following RRV infection.