On Nov. 5, 2025, the World Health Organization (WHO) reported that between 20 September and 30 October 2025, a total of 404 confirmed human cases of Rift Valley fever (RVF), including 42 deaths, were reported by national health authorities in two West African countries: Mauritania and Senegal.

RVF is a zoonotic disease, which mainly affects animals, but can also infect humans. The majority of human infections result from contact with the blood or organs of infected animals, but human infections have also resulted from the bites of infected mosquitoes.

To date, no human-to-human transmission of RVF has been documented. While RVF often leads to severe illness in animals, its impact in humans varies, ranging from mild flu-like symptoms to severe hemorrhagic fever that can be fatal. RVF is endemic in both countries, where recurrent outbreaks have been previously reported in both livestock and humans.