In its weekly epidemiologic profile of the outbreak today, the World Health Organization (WHO) said Ebola activity in Guinea and Sierra Leone has become more intense and widespread since May 10, when the region saw cases hit a 10-month low.
Last week the two countries reported 25 new lab-confirmed cases, 13 in Guinea and 12 in Sierra Leone. The number is up from 12 reported the week before.
Overall, the total of confirmed, probable, and suspected cases in the two countries and Liberia—which is now Ebola free—has risen to 27,145, including 11,147 deaths, the WHO said.
No health worker infections were reported, keeping the total at 869, 507 of them fatal.
Concerns over unknown transmission chains
The WHO said several of the new cases are from unknown sources in areas that haven’t reported any confirmed cases in several weeks. It said rigorous contact tracing, active case finding, and infection prevention and control are needed to break transmission chains and get cases down to zero, but the onset of rainy season will make field operations more difficult in the weeks and months ahead.