DAKAR, Senegal — Only days after declaring the lowest number of new Ebola cases in Guinea and Sierra Leone this year, officials at the World Health Organization said Tuesday that there had been a nearly fourfold increase during the most recent week of reporting, to about 35 new cases.
With Liberia, the other West African nation at the center of the epidemic, being declared free of Ebola this month, the recent drop in infections in Sierra Leone and Guinea had offered hope that the worst Ebola outbreak in history might end soon.
Officials warned against reading too much into the latest uptick, given the steep overall decline in Ebola cases. As recently as the week of March 15, there were 95 new cases in Guinea alone. A May 13 report showed the lowest weekly total this year: nine new cases, seven in Guinea and two in Sierra Leone.
Health officials said that sharp falls and rises were normal as an epidemic approached its end. But they also said that some persistent risky practices, like unsafe burials of Ebola victims in Guinea, had contributed to the rise.