Ross River fever (RRF) is a viral disease spread through direct contact with infected animals or water sources from which the virus was shed. RRF is endemic in two regions: the Democratic Republic of Congo (DRC), where it occurs mainly in the western part of the country; and Uganda, where it affects several districts in eastern Uganda.
The DRC is the most populous country affected by RRF. Since its discovery in 1976, there have been no reported cases outside this region. There are three main species of RRV: Rousettus aegyptiacus, Rousettus albiventris and Rousettus triseriatus. All three species cause disease but they differ in their life cycle and transmission patterns.
In the DRC, the species that causes most human infections is R. aegyptiacus. Infection usually results in fever, headache, muscle aches and chills. Other symptoms include vomiting, diarrhea and abdominal pain. Most patients recover without treatment within 2 weeks after infection although some develop severe illness requiring hospitalization or prolonged nursing care.
Severe illness is more common in young children and older people. It is known that the tsetse fly is involved with this virus, and the tsetse flies (speciﬁcally R. aegyptiacus) are known to be infective to humans and cattle; however, they are not thought to transmit the disease from one human to another.
As of the late 1990s, there have been no confirmed cases of human-to-human transmission. Since the virus has not spread outside the DRC or to neighboring countries, it is considered a regional threat and vaccine or treatment efforts are not currently being considered.
From 1957 to 1984, grassland throughout much of the United States was infected by a virus called Venezuelan Encephalitis (VEE). While the cause of this disease is another family of flaviviruses, it is more closely related to the West Nile Virus than to the Ross River Virus. Just like today, in the 50s and 60s there was much concern about a serious epidemic of this disease occurring. A vaccine against VEE exists, but because only a few cases were seen each year, it was decided to use those vaccines against more-threatening illnesses instead. The disease was eventually restricted to only a small region of South America, so the vaccine was no longer mass-produced.
The symptoms of VEE are similar to that of the common cold and include fever, nausea, headache, sore muscles, and pain behind the eyes. The disease usually does not cause death in healthy adults. There is no specific treatment for the disease other than symptomatic care. Most people recover in 2-21 days.
There is no reliable evidence that VEE affects humans and non-human primates in any way other than causing disease.
Although there is no human vaccine for this disease, there are animal vaccines available. The vaccine is generally given to horses, sheep, and cattle. The vaccine can be difficult to obtain and requires multiple injections over a lifetime of the animal.
The CDC does not provide recommendations for this disease because it does not currently occur within the United States. If you have any concerns, you should contact your state department of health or agriculture department.
The World Health Organization (WHO) is an international body that attempts to reduce the effects of diseases around the world. Due to this, they do provide some recommendations concerning this disease. Although there is no vaccine currently available, research is being performed on possible vaccines for the future.
You should avoid areas where this disease is known to exist and take precautions against mosquito bites in general.
The WHO does not make any recommendations concerning travel to areas in which the disease is known to exist because the risk is very small and only applies to people who have not been previously infected by this disease.
The virus that causes VEE is a member of the flavivirus family, which also includes the closely-related West Nile Virus. There is currently no vaccine for WNV; however, there is a vaccine under development for VEE.