The World Health Organization has sent a six-person team and 40 boxes of personal protective gear to help fight a major outbreak of Lassa fever in Nigeria.
About 615 suspected Lassa cases have been reported in the last six weeks, according to the Nigeria Center for Disease Control; 57 have been fatal. Fourteen health care workers have been infected, and four have died.
Health authorities are also following about 1,400 contacts of confirmed cases.
The outbreak is concentrated in the nation’s southwest, but cases have been found in 17 of the country’s 36 states. For the first time in five decades, the disease has been found in northeastern Borno State, where the Nigerian army is fighting Boko Haram militants.
The new team will join 14 local W.H.O. staffers at the emergency operations center of Nigeria’s C.D.C., the agency said last week. It is also sending reagents for Nigeria’s laboratories to speed up diagnoses.
Many infections with Lassa virus are mild, but it can also cause lethal hemorrhagic fevers resembling those of Ebola.
The most common carrier is a rodent of the Mastomys species, 4 to 7 inches long and with 24 mammary glands. It lives mostly in rural areas; in some African countries, it is known as a “multimammate mouse” and in others as a “soft-furred rat.”
The government is encouraging villagers to store grain in sealed containers, to cook food thoroughly and to keep rodents out of homes.
As with Ebola, a heavily infected patient’s blood, urine, vomit and other fluids can teem with Lassa virus, and transmission between people often takes place in rural hospitals where protective gear is not available.
Experts believe the virus can also be sexually transmitted. About a quarter of all patients who get a serious attack and survive are left deaf.
Lassa fever is endemic in West Africa. Benin, Guinea, Liberia and Sierra Leone have all reported cases in the past month.
Last year, the Bill and Melinda Gates Foundation, the Wellcome Trust and the governments of Japan and Norway joined forces with six vaccine companies to form the Coalition for Epidemic Preparedness Innovations. Lassa fever was one of the first three diseases they chose to seek a vaccine against, because they felt it was so threatening. (The others were Middle East respiratory syndrome and Nipah virus.)