A new viral threat is looming over Africa. Cases of Lassa fever, a deadly hemorrhagic disease, are exploding in Nigeria, and the virus is expanding its range.
Long neglected as an obscure West African disease, Lassa fever has vaulted up on the international agenda, landing a spot on the World Health Organization’s list of the world’s most dangerous pathogens for which no vaccine or drugs exist. The Coalition for Epidemic Preparedness Innovations has made Lassa fever one of its top priorities and is trying to develop the first-ever vaccine. No specific treatment exists.
This zoonotic virus is mainly transmitted by direct contact with its host, the common African rat, or its excreta. But the virus also spreads person to person, a huge risk for health care workers. Most cases are asymptomatic, but up to 60% of those with severe disease die. Many suffer permanent hearing loss.
Researchers are scrambling to understand what’s driving the upsurge. Is it a change in the virus or in the rodents that carry it? A change in human behavior?
A huge study in five African countries is trying to determine Lassa’s true burden. Estimates range from 100,000 to 4 million cases a year. Meanwhile, a new study suggests that with population growth and changes in climate and land use, the virus could spread across Central and East Africa in the coming decades, putting up to 600 million people at risk.
Science magazine will document the urgent efforts underway in Nigeria and Sierra Leone to understand what is driving the Lassa fever epidemics and how to treat the disease and stop its spread.
