Rift Valley fever is an acute viral disease that affects both humans and domestic animals, including cattle, buffalo, sheep, goats, and camels. It is linked to mosquito-borne outbreaks, particularly during periods of heavy rainfall. This illness is considered more lethal than the West Nile virus. Although Rift Valley fever has not been documented in the United States up to 2003, there is concern that it could establish itself permanently if it were to arrive. Infected individuals often exhibit flu-like symptoms but can occasionally suffer from severe complications such as kidney issues. The mortality rate during outbreaks is approximately 15% among those severely affected.The disease is caused by the Rift Valley fever virus, predominantly found in eastern and southern Africa where livestock like sheep and cattle are common. It primarily impacts livestock, leading to widespread illness within domestic animal populations, referred to as an "epizootic." When such an outbreak occurs, it can also trigger an epidemic among humans who are in contact with infected animals. The most significant epizootic occurred in Kenya between 1950 and 1951, resulting in the death of around 100,000 sheep. The first recorded epidemic in West Africa was in 1987.Rift Valley fever outbreaks often coincide with heavy rainfall and localized flooding, which facilitate the hatching of mosquito eggs, typically of the Aedes genus. These mosquitoes carry the RVF virus and transmit it to livestock. Once the animals are infected, other mosquito species can spread the virus further.Humans contract RVF primarily through mosquito bites, but it is also possible through contact with blood or bodily fluids from infected animals, often during slaughtering or handling. Aerosol transmission has occurred in laboratories handling the virus.Most people with RVF experience no symptoms or only mild ones, such as fever and liver irregularities. Those with severe symptoms may face fever, weakness, dizziness, and significant weight loss. Recovery generally occurs within two days to a week. However, RVF can escalate to hemorrhagic fever, encephalitis, or eye disease, leading to a 1% mortality rate among infected individuals.A common long-term issue involves the eye, caused by inflammation of the retina, with 1-10% of affected individuals suffering some permanent vision loss. There is no established treatment for RVF, although Ribavirin has shown potential in animal studies. Interferon, immune modulators, and convalescent-phase plasma may also aid in treatment efforts.Sleeping outdoors in outbreak regions increases exposure risk to mosquito vectors. Those who work closely with animals, like herdsmen and abattoir workers, face a higher infection risk. Professionals such as veterinarians and slaughterhouse workers are particularly at risk of contracting the virus from infected animals.International travelers visiting RVF-endemic areas during active cases or epidemics have a higher chance of contracting the disease. To prevent infection, using mosquito repellents and bed nets is strongly advised, and avoiding contact with the blood and tissues of potentially infected animals is crucial.
