LAGOS, Nigeria

Nigeria declared an emergency because of Lassa fever, according to the National Centre for Diseases Control (NCDC).

NCDC said late Wednesday in an alert that it activated the national Multi-sectoral Emergency Operations Centre for Lassa Fever to coordinate and strengthen ongoing response activities.

NCDC Director General Chikwe Ihekweazu said earlier that the emergency declaration was informed by a risk assessment conducted Jan. 20 by the Center.

"An unprecedented upward trend in the number of confirmed cases being reported compared to previous years," he said.

A total of 244 confirmed cases of Lassa fever were reported with 37 related deaths in January, said the Centre.

It released a national guideline for the control, management and treatment of Lassa fever.

Lassa fever is an acute viral disease transmitted by common African rodents and endemic in African nations, including Nigeria, Sierra Leon, Guinea and Liberia, according to medical experts.