With the Ebola Virus Disease (EVD) outbreak in Guinea, Sierra Leone, Liberia, Nigeria and Senegal, we have some good news and some not so good news from the World Health Organization (WHO).

Liberia Ebola  public service poster/CDC
Liberia Ebola public service poster/CDC

First the good news.

The Ebola outbreaks in Nigeria and Senegal are very close to being officially over. The WHO says if the active surveillance for new cases that is currently in place continues, and no new cases are detected, WHO will declare the end of the outbreak of Ebola virus disease in Senegal on Friday, 17 October. Likewise, Nigeria is expected to have passed through the requisite 42 days, with active surveillance for new cases in place and none detected, on Monday, 20 October.

The period of 42 days, with active case-finding in place, is twice the maximum incubation period for Ebola virus disease and is considered by WHO as sufficient to generate confidence in a declaration that an Ebola outbreak has ended.

Recent studies conducted in West Africa have demonstrated that 95% of confirmed cases have an incubation period in the range of 1 to 21 days; 98% have an incubation period that falls within the 1 to 42 day interval. WHO is therefore confident that detection of no new cases, with active surveillance in place, throughout this 42-day period means that an Ebola outbreak is indeed over.

Now the not so good news.

During a news conference in Geneva Tuesday, WHO assistant director-general Dr. Bruce Aylward said West Africa could face up to 10,000 new Ebola cases a week within two months.

In addition, Aylward added the death rate in the current outbreak has risen to 70 percent.

The Ebola case and death total in has climbed to more than 8,900 cases and 4,447 fatalities (the vast majority in West Africa).