The World Health Organization has shut one of its Ebola testing labs in Sierra Leone after a staff member there was infected by the virus.
The WHO said Tuesday it has withdrawn its staff from the lab in Kailahun - one of only two in Sierra Leone - after a Senegalese epidemiologist was infected with the deadly virus. The move could adversely affect efforts to contain the worst ever outbreak of the disease.
Ebola has killed more than 1,400 people and sickened more than 2,600 in West Africa since the outbreak began in March.
Among the worst affected countries are Sierra Leone, Guinea and Liberia, where the government has sealed off an entire slum in the capital Monrovia.
In Liberia, where the highest number of deaths has been reported, some government officials are fleeing the country or just not reporting for work. The situation drove President Ellen Johnson Sirleaf on Tuesday to order all ministers to return to work.
Liberian officials said several ministers who defied the order had been fired.
Dr. Tom Frieden, head of the U.S. Centers for Disease Control and Prevention, offered a cautionary assessment of the outbreak while meeting with officials in Liberia.
Some information for this report comes from AP, AFP and Reuters.