The Nigeria Federal Ministry of Health is reporting an increase in Lassa fever in 2016 to date, according to the latest data from the Nigeria Centre for Disease Control.

Nigeria map divided by states/United Nations
Nigeria map divided by states/United Nations

During the first six months of 2016, the west African country reported 744 suspected Lassa fever cases with 72 lab-confirmed and 87 deaths with a case-fatality rate of more than 11 percent. This compares to the same period in 2015 when 156 suspected cases with 9 lab-confirmed and 5 deaths were reported.

Lassa is also more widespread this year with cases reported in 27 states, while last year, only 10 states were affected.

Edo State has been hit hardest with 288 cases, followed by Ondo (82) and Niger (59) states. Niger state has recorded the most fatalities with 19.


According to the US Centers for Disease Control and Prevention (CDC), Lassa fever is an acute viral illness that occurs in West Africa. The virus, a member of the virus family Arenaviridae, is a single-stranded RNA virus and is zoonotic, or animal-borne.

Lassa fever is a significant cause of morbidity and mortality. While Lassa fever is mild or has no observable symptoms in about 80% of people infected with the virus, the remaining 20% have a severe multisystem disease.

The animal host of Lassa virus is a rodent known as the “multimammate rat” of the genus Mastomys. Humans get infected with Lassa through aerosol or direct contact with excreta from the rodent. Laboratory infections do occur primarily through contaminated needles.

The symptoms of Lassa fever typically occur 1-3 weeks after the patient comes into contact with the virus. These include fever, retrosternal pain (pain behind the chest wall), sore throat, back pain, cough, abdominal pain, vomiting, diarrhea, conjunctivitis, facial swelling, proteinuria (protein in the urine), and mucosal bleeding. Neurological problems have also been described, including hearing loss, tremors, and encephalitis.

The Lassa virus and was 1st described in 1969 in the town of Lassa, in Borno State, Nigeria.

Ribavirin has been used successfully in the treatment of confirmed Lassa cases. This drug can treat infected people if it is administered as soon as the first signs appear.