New Lassa fever infections fall but case fatality rate jumps as Nigeria continues to battle outbreak

As Nigeria continues to battle an outbreak of Lassa fever, the number of new infections dropped to 65 in the last week of February, the country’s Centre for Disease Control (NCDC) said on Monday, down from 77 the week before. 

But the case fatality rate has jumped to more than 23 percent, up from just under 19 percent during the same period last year.  

The agency said this was likely due to people waiting too long to seek treatment. It also pointed to poor sanitation and low-information awareness in high-burden communities. 

The NCDC says it’s supporting local authorities with increased surveillance and contact tracing, and deploying rapid response teams to infection hotspots. Personal protective equipment is being distributed to health facilities. 

People between the ages of 21 and 30 are the most affected. Infections among health care workers have also risen.

Lassa fever belongs to the same family as Marburg and Ebola, two deadly viruses that lead to infections with fever, vomiting and, in worse case scenarios, hemorrhagic bleeding. Its name is from the town of Lassa in northern Nigeria where it was first identified in 1969.

Endemic to the region, Lassa fever is asymptomatic in 80 percent of cases but for others it can cause internal bleeding, especially when diagnosed late.

There are no licenced vaccines for Lassa fever.