Ebola is no longer a world health emergency, WHO says

(CNN) -- The Ebola outbreak in West Africa, at one time considered the worst outbreak in history, is no longer a public health emergency of international concern, the World Health Organization said on Tuesday.

The announcement came after an emergency committee meeting to review the situation in key countries: Sierra Leone, Liberia and Guinea.

"The committee noted that since its last meeting, all three countries have met the criteria for confirming interruption of their original chains of Ebola virus transmission," WHO said. "Specifically, all three countries have now completed the 42-day observation period and additional 90-day enhanced surveillance period since their last case that was linked to the original chain of transmission twice tested negative."

As expected, there have been "flare-ups" and a handful of new cases, most recently in Guinea, that relate to a new single chain of transmission. That case has infected eight people and seven of them have died.

The committee reviewed the data from those cases and determined that there is enough expertise on the ground to contain the spread, meaning the risk of the current cases leading to the spread of the disease is low. A genetic trace of the Ebola virus can live on in someone's semen for a little over a year after the person has experienced initial symptoms of the disease, but it is at a low level.

The committee said it believes there will soon be even fewer of these clusters.

As of March 2016, about 11,320 people had died in the epidemic. Guinea lost 2,540 people, Sierra Leone lost 3,956 and Liberia lost 4,809 and there were a handful of deaths in other countries, including in Nigeria, where there were eight cases. Mali lost six people and the United States lost one, according to the Centers for Disease Control and Prevention.

Two countries at the heart of the epidemic have been declared free of the Ebola virus for months. WHO declared Liberia free of Ebola virus transmission on May 9, 2015. Sierra Leone was declared free of Ebola virus transmission in November. There were two cases reported in January of this year, but the country was free of new Ebola cases as of March 17.

Guinea went on that list December 29, 2015, but fell off when eight patients related to the same case popped up. All but one of those cases were in the same village, and with the measures on the ground, the disease was considered under control as of March 27.

WHO Director General Margaret Chan said any remaining travel or trade restrictions put in place at the height of the epidemic to help limit the spread of the deadly virus should be lifted.

The WHO also urged the international health community to keep up the fight against future outbreaks of the disease and to continue work on a vaccine.