Why in news?
The World Health Organisation has reported an outbreak of Rift Valley Fever (RVF) in Mauritania and Senegal between late September and October 2025. More than four hundred human cases and dozens of deaths have been confirmed, along with hundreds of animal infections. The disease, which primarily affects livestock, can spill over to humans and has prompted an emergency response in both countries.
Background
Rift Valley Fever is a viral disease first identified in Kenya’s Rift Valley in 1931. It is caused by a Phlebovirus in the family Bunyaviridae. The virus infects domesticated animals—particularly sheep, goats, camels and cattle—and can lead to high mortality in newborn animals and abortions in pregnant females. Humans usually become infected through contact with the blood, organs or raw milk of infected animals. Mosquito bites can also transmit the virus, especially during heavy rains when mosquito populations increase. There is no evidence of sustained human‑to‑human transmission.
Outbreak details
- Case numbers: Mauritania reported 46 human cases with 14 deaths, while Senegal reported 358 human cases with 28 deaths. Hundreds of animal cases were also recorded, particularly in the Saint‑Louis region of Senegal and the Assaba and Hodh El Gharbi regions of Mauritania.
- Symptoms in humans: Most infected people develop a flu‑like illness with fever, headache and muscle pain. A small proportion can develop severe complications such as hemorrhagic fever, encephalitis (brain swelling) or vision loss.
- Risk factors: People who slaughter animals, handle raw meat or live near infected livestock are at highest risk. Occupational exposure on farms and in slaughterhouses is common.
- One Health response: Authorities are using a coordinated approach that involves human health, veterinary and environmental sectors. Measures include vaccinating livestock, controlling mosquitoes, restricting animal movements, enhancing surveillance and educating communities about safe handling of animals.
Prevention and control
- Avoiding exposure: People should wear gloves and protective clothing when handling animals or raw meat and avoid consuming unpasteurised milk or undercooked meat.
- Mosquito control: Eliminating standing water, using bed nets and applying insect repellents help reduce mosquito bites.
- Animal vaccination: Vaccinating susceptible livestock before periods of heavy rain helps prevent outbreaks in animals and reduces the risk of human infections.
- Surveillance: Early detection of cases through laboratory testing and rapid reporting enables quick containment of outbreaks.
Conclusion
Rift Valley Fever highlights the close link between human health, animal health and the environment. Timely detection and coordinated action among health, veterinary and environmental authorities are essential to control outbreaks and protect both livelihoods and public health.
Source: World Health Organisation