The death toll of Lassa fever in Nigeria in 2022 has risen to 171, despite measures by the government to reduce infections across the country, the Nigeria Center for Disease Control (NCDC) said on Sunday.

In its latest Lassa fever situation report, the NCDC said there have been a total of 917 confirmed cases, with 6,660 suspected cases recorded since the beginning of 2022. In the week from September 5 to 11 alone, eight new confirmed cases and one death were recorded.

So far, 25 states have recorded at least one confirmed case across 102 out of the 774 local government areas in the most populous African country, the public health agency said.

With the death toll rising to 171, the NCDC said the case fatality rate was 18.6 percent, lower than that for the same period in 2021, which was 23.3 percent.

The disease control center said the predominant age group affected is 21-30 years, with the male-to-female ratio for confirmed cases being 1:0.8.

According to the World Health Organization, Lassa fever is an acute viral hemorrhagic illness caused by the Lassa virus, a member of the arenavirus family of viruses. 

Humans usually become infected with the Lassa virus through exposure to food or household items contaminated with urine or feces of infected Mastomys rats. 

The disease is endemic in the rodent population in parts of West Africa.