A picture shows a warning and awareness banner for Lassa fever displayed at the Institute of Lassa Fever Research and Control in Irrua Specialist Teaching Hospital in Irrua, Edo State, midwest Nigeria, on March 6, 2018. (Pius Utomi Ekpei/AFP via Getty Images)

Lassa Fever Death Toll Reaches 41 in Nigeria

The death toll from a Lassa fever outbreak in northern Nigeria has risen to 41, the Nigeria Center for Disease Control (NCDC) announced this week.

There are 258 confirmed cases of the infectious disease across 19 of Nigeria’s 36 states, the NCDC said. Most of those affected are between 11 and 40 years old.

NCDC said it has activated emergency operations centers (EOC) in response to the outbreak, and rapid response teams have been deployed to support activities in five states. The health institute said it’s “working to support every state in Nigeria to identify one treatment center, while supporting existing ones with care, treatment, and IPC commodities.”

What Is Lassa Fever?

According to the World Health Organization, Lassa fever is “an acute viral hemorrhagic illness caused by Lassa virus, a member of the arenavirus family of viruses,” and was first identified in 1969 and named after the town in Nigeria where it was discovered.

Humans typically become infected by the virus through exposure to food or household items contaminated by the urine or feces of infected Mastomys rats.

Samples of rodents that spread Lassa fever are displayed at the Institute of Lassa Fever Research and Control in Irrua Specialist Teaching Hospital in Irrua, Edo State, Nigeria, on March 6, 2018. (Pius Utomi Ekpei/AFP via Getty Images)

Mastomys rats breed frequently, produce large numbers of offspring, and are commonly found in the savannas and forests of west, central, and east Africa.

However, direct contact with infected rodents isn’t the only way for people to be infected, as person-to-person transmission may occur after exposure to the virus in the blood, tissue, secretions, or excretions of a Lassa virus-infected individual, the U.S. Centers for Disease Control and Prevention states.

Roughly 80 percent of people who become infected with Lassa virus have no symptoms, while one in five infections result in severe disease, in which the virus affects several organs, such as the liver, spleen, and kidneys.

Signs and Symptoms

Signs and symptoms of Lassa fever typically occur between one and three weeks after the patient is exposed to the virus and for the majority (approximately 80 percent), symptoms are mild and go undiagnosed.

Individuals may suffer mild symptoms such as a slight fever, discomfort, weakness, and headaches. The disease can progress to more serious symptoms including hemorrhaging in the gums, eyes, or nose, respiratory issues, repeated vomiting, facial swelling, pain in the chest, back, and abdomen, and shock.

Loss of hearing, tremors, and encephalitis, an inflammation of the brain, can also occur, while death may occur two weeks after the symptoms begin, due to multi-organ failure.

While about 15 to 20 percent of patients who are hospitalized for Lassa fever die from the illness, only 1 percent of all Lassa virus infections result in death, the CDC says. Women in the third trimester of pregnancy are at an increased risk of death from the infection.

Previous Cases

Lassa virus is an annually recurring viral disease and different from the current outbreak of coronavirus that was first diagnosed in the Chinese city of Wuhan in December last year.

An estimated 100,000 to 300,000 infections of Lassa fever occur annually, resulting in approximately 5,000 deaths, according to the CDC.

Treatment

Lassa virus can be treated by the antiviral drug Ribavirin, which is most effective when provided promptly after the patient becomes sick.

Preventative steps to avoid exposure to the virus include storing food in rat-proof containers and keeping the home clean to discourage rats from entering. Health officials also advise not to eat the rats, which are sometimes consumed as a food source.