The World Health Organization (WHO) said on Tuesday it had shut a laboratory in Sierra Leone after a health worker there was infected with Ebola, a move that may hamper efforts to boost the global response to the worst-ever outbreak of the disease.

At least 1,427 people have died and 2,615 have been infected since the disease was detected deep in the forests of southeastern Guinea in March.

The WHO has deployed nearly 400 of its own staff and partner organisations to fight the epidemic of the highly contagious hemorrhagic fever, which has struck Sierra Leone, Liberia, Guinea and Nigeria. A separate outbreak was confirmed in Democratic Republic of Congo on Sunday.

One of the deadliest diseases known to man, Ebola is transmitted by contact with body fluids. The current outbreak has killed at least 120 healthcare workers.

#Ebolavirus under electron microscope

The WHO said it had withdrawn staff from the laboratory testing for Ebola at Kailahun – one of only two in Sierra Leone – after a Senegalese epidemiologist was infected with Ebola.

“It’s a temporary measure to take care of the welfare of our remaining workers,” WHO spokeswoman Christy Feig said, without specifying how long the measure would last.

“After our assessment, they will return.”

Feig said she could not assess what impact the withdrawal of WHO staff would have on the fight against Ebola in the Kailahun, the area hardest hit by the disease. The WHO said in a later statement that staff would return after an investigation was completed, adding that testing would continue in the meantime at the Kenema laboratory.

The Senegalese medic – the first worker deployed by WHO to be infected – will be evacuated from Sierra Leone in the coming days, Feig said. He is currently being treated at a government hospital in the eastern town of Kenema.

Separately, Public Health Agency of Canada spokesman Sean Upton said late on Tuesday the agency was planning to withdraw its three-person mobile laboratory team from Sierra Leone. The agency could not confirm immediately whether the lab was a different one from the laboratory that the WHO closed.

The Canadian team was recalled because three people in their hotel complex were diagnosed with Ebola, although Upton said none of the Canadians had direct contact with any of the sick people and were not showing any symptoms of Ebola.

With its resources stretched by the West African outbreak, medical charity Medecins Sans Frontieres (MSF) said on Tuesday it could provide only limited help to tackle Congo’s outbreak.

A report from the U.N. mission in Congo on Tuesday said 13 people there had died from Ebola, including five health workers.

Congo said on Sunday it would quarantine the area around the town of Djera, in the isolated northwestern jungle province of Equateur, where a high number of suspected cases has been reported. It is Congo’s seventh outbreak since Ebola was discovered in 1976 in Equateur, near the Ebola river.