The Ebola outbreak in the Democratic Republic of Congo is over, the World Health Organization confirmed Friday.

WHO officials made the declaration after no new cases of the deadly virus were reported in the last 42 days- double the 21 day incubation period when symptoms usually occur, according to the Wall Street Journal.

"Having reached that 42-day mark, the Democratic Republic of Congo is now free of Ebola transmission," the WHO said.

While the battle against the disease was focused on Sierra Leone, Guinea and Liberia- the center of the Ebola epidemic- the DRC dealt with a separate outbreak of the virus that began in August. The central African nation saw 66 cases of the disease and 49 deaths, eight being healthcare workers, the WSJ reported.

This was the seventh time the DRC suffered an Ebola outbreak since the disease was first identified there in 1976.

The fight against Ebola in West Africa, however, is far from over.  Over 15,000 cases have been reported and 5,420 people have died in Sierra Leone, Guinea and Liberia, according to a WHO report released Wednesday.

Ebola, of which there is no official cure, is "increasing exponentially" in Sierra Leone, especially in the capital Freetown, U.N. Under Secretary General Kandeh Yumkella told CNN.

Bur the former Sierra Leone trade minister also said he was "cautiously optimistic" about containing the virus, a feat that depends on a swift and organized response.

"WHO commends the Democratic Republic of Congo's strong leadership and effective coordination of the response that included rapidly mobilizing an expert response team to Jeera County, identifying and monitoring contacts and organizing safe burials," the organization said according to Reuters.