Maps of Angola showing month-to-month spread of yellow fever. Courtesy the World Health Organization. Yellow fever is a persistent problem in West Africa, where the virus cycles between monkeys ...

is thought to cause between 20,000 and 180,000 deaths a year in Africa. Researchers have previously used environmental measures to map areas most at risk of yellow fever outbreaks. In the new work ...

L ONDON — The World Health Organization says the ongoing outbreak of yellow fever in central Africa is “serious and of great concern” but does not warrant being declared a global emergency.