Senegal has recorded 17 deaths and 119 cases of Rift Valley Fever (RVF), largely in the livestock-producing north, in what health officials say is the country’s deadliest outbreak in decades.
Dr Boly Diop, who leads RVF surveillance at the health ministry, said the concentration of cases in northern regions has raised fears of wider spread. The outbreak was declared on Sept. 21, according to the Africa Centres for Disease Control and Prevention (Africa CDC), which said the response has been slowed by low community awareness, weak early warning and late case detection.
RVF is a mosquito-borne viral disease that primarily affects animals. The World Health Organization says no human-to-human transmission has been documented; people are typically infected by mosquito bites or contact with blood, body fluids or tissues of infected animals. Those most at risk include herders, farmers, slaughterhouse workers and veterinarians.
“RVF has been endemic in northern Senegal since the 1980s,” Dr Merawi Aragaw Tegegne, an Africa CDC epidemiologist, told a weekly briefing. “It has become more frequent across Africa, closely linked to climate change and extreme weather.” He said alternating episodes of torrential rain and quick floods followed by sunny days create ideal conditions for the mosquitoes that carry the virus.
An RVF epidemic in 1987–88 killed more than 200 people in Senegal and Mauritania. Since then, Senegal has seen only minor flare-ups. “This is the first time Senegal has counted so many people affected,” Diop said.
Most human infections are mild, the WHO says, but severe disease can occur, including an ocular form that may cause vision loss and a haemorrhagic form with a case fatality rate of about 50%.