The outbreak of Ebola in the Democratic Republic of the Congo is probably over, with no new cases reported for three weeks, the World Health Organization said Friday.
WHO called the outbreak “largely contained.” But it’s too soon to declare the outbreak fully ended because it’s possible someone has been infected and has not started showing symptom yet, the WHO said.
WHO said 53 people had been infected with the virus and 29 had died. The last confirmed case was treated and released on 12 June.
No one appears to have carried the virus out of the country and WHO is lowering the risk advisory to neighboring countries. The risk of wider export out of the region was never considered high.
“In the absence of ongoing transmission, the probability of exported cases is low and diminishing,” WHO said.
WHO said more than 3,300 people had been given an experimental Ebola vaccine, using a technique called ring vaccination, in which cases of the disease are tracked down and all the people they have been in direct contact with are vaccinated. Then the contacts of those vaccinated people are tracked down and vaccinated. This method eradicated smallpox at the end of the 1970s.
This was the ninth outbreak of Ebola in the Democratic Republic of the Congo. Until this one, the outbreaks had been in remote regions and affected usually fewer than 100 people, although a 1995 outbreak sickened 315 people and killed 250 of them and the first outbreak, in 1976, affected 318 people and killed 280.
Health experts were worried about this outbreak because cases were seen in a large city, Mbandaka, which sits on the busy Congo River.
Urban outbreaks of Ebola are especially frightening. In 2014-2016 an epidemic of Ebola sickened more than 28,000 people and killed more than 11,000 of them in Liberia, Guinea and Sierra Leone. It spread explosively in both urban and rural regions.
Quick reaction probably helped contain this outbreak, experts said.
“However, there remains a risk of resurgence from potentially undetected transmission chains and possible sexual transmission of the virus by male survivors. It is therefore, critical to maintain all key response pillars until the end of the outbreak is declared,” WHO said.
“Before the outbreak can be declared over, a period of 42 days (two incubation periods) following the last possible exposure to a confirmed case must elapse without any new confirmed cases being detected."
Ebola can pop up unexpectedly because it can survive in male semen for months after a man has recovered from an infection.
WHO also said it was helping the Congolese Ministry of Health to set up a year of care for Ebola survivors, who can suffer long-term symptoms.