Kenya is among six nations facing the highest risk of an outbreak of the Rift Valley Fever (RVF) disease, a United Nations agency has warned, putting pressure on health and veterinary authorities to prevent another spate of the highly contagious virus.
The UN’s Food and Agriculture Organisation (FAO) and the Intergovernmental Authority on Development (IGAD) urged Kenya and other countries across Eastern Africa to strengthen preparedness and surveillance measures as heavy rainfall and flooding associated with El Niño increase the risk of RVF outbreaks.
‘The countries currently assessed as facing the highest risk are Ethiopia, Kenya, Somalia, South Sudan, Tanzania and Uganda. Risk is also increasing in Burundi and Rwanda, while lower but growing risks exist in the Comoros, northern Madagascar, the Department of Mayotte, south-western Saudi Arabia and western Yemen,’ the agencies said.
The Kenya Meteorological Department has forecast above-average rainfall across the country during the October-December 2026 season, due to the El Niño phenomenon.
RVF is an acute viral disease that affects livestock, including sheep, goats, cattle, buffaloes and camels, and can also infect humans. The virus is transmitted mainly by mosquitoes, while the movement of infected animals can contribute to its geographical spread.
The viral zoonotic disease also spreads from animals to humans, primarily through contact with infected animal blood, body fluids, or tissues, and via mosquito bites.
Kenya suffered its most recent episodes of RVF outbreaks in 2020/2021 and 2023/2024, which affected livestock and humans, with deaths reported. The country suffered its worst RVF outbreak in the 1997-1998 window after heavy rainfall and severe flooding triggered a massive viral transmission.
‘Based on the October 2026 forecast of the FAO RVF Early Warning Decision Support Tool (RVF DST), conditions suitable for RVF transmission are expected to increase across much of Eastern Africa between October 2026 and January 2027,’ the agencies said.
‘Following a long period of rainfall deficits, rainfall has picked up in recent weeks in parts of southern Sudan, western South Sudan, eastern Ethiopia, southern Somalia and coastal Kenya, with heavy rains and a rising flood risk in Ethiopia and Somalia.’
According to the World Health Organisation, most RVF human infections result from direct or indirect contact with the blood or organs of infected animals. The virus can be transmitted to humans through the handling of animal tissue during slaughtering or butchering, assisting with animal births, conducting veterinary procedures, or from the disposal of carcasses or fetuses.
‘Certain occupational groups such as herders, farmers, slaughterhouse workers and veterinarians are therefore at higher risk of infection. There is some evidence that humans may become infected with RVF by ingesting the unpasteurised or uncooked milk of infected animals,’ the WHO said.
In humans, the interval from infection to onset of symptoms for RVF varies from 2 to 6 days. The WHO said that most RVF infections in humans will lead to no symptoms or a mild form of the disease characterised by a feverish syndrome with sudden onset of flu-like fever, muscle and joint pain and headache.
Some patients develop neck stiffness, sensitivity to light, loss of appetite and vomiting. In these patients, the disease, in its early stages, may be mistaken for meningitis.
FAO says that in livestock, the initial signs of RVF will depend upon the breed, age and genotype of the target animals. However, a sudden onset of abortions among sheep, goats, cattle or camels over a wide area is probably the most significant sign.
‘There will also probably be sudden deaths and disease with many fatalities in all species, especially in the early post-natal period. Nearly 100 percent of young lambs of susceptible breeds may die. Older animals at one to four months may suffer an acute febrile disease with prostration and 10-40 percent fatalities,’ the UN agency said.