Nigeria Experiencing Biggest Lassa Fever Outbreak To Date

Nigeria is fighting its biggest outbreak of Lassa fever, to date, according to new reports from the World Health Organization (WHO) and the Nigeria Centre for Disease Control (NCDC).

Lassa fever is a virus spread to humans through the handling of food or other items contaminated with the feces or urine of infected Mastomys rats. The disease has an incubation period of 2 to 21 days, and most infections are mild, with symptoms including fever, general weakness, and malaise at onset. As the infection progresses, symptoms may include headache, sore throat, muscle pain, nausea, vomiting, diarrhea, cough, and abdominal pain. In more severe cases, individuals may experience facial swelling, fluid in the lung cavity, and bleeding from the mouth, nose, vagina, or gastrointestinal tract. Late-stage Lassa fever can include shock, seizures, tremor, disorientation, and coma, and can be deadly, typically within 14 days of onset. About 25% of individuals who survive the infection experience deafness, which can partially subside within 1 to 3 months. Lassa fever can be treated with the antiviral drug ribavirin early in the course of illness.

Since the discovery of the virus in 1969, outbreaks of Lassa fever have occurred in West African countries including Nigeria, Guinea, Liberia, Mali, Ghana, and Sierra Leone, where the disease is endemic.

Nigeria experienced an outbreak of Lassa fever starting in August 2015, which as of May 2016 saw 273 reported cases and 149 deaths.

On February 28, 2018, WHO and NCDC health officials reported that Nigeria is experiencing a record outbreak of Lassa fever. The first case was detected on January 1, 2018, and the outbreak has since spread to 18 states, causing 317 laboratory-confirmed cases and resulting in 72 deaths. A previous report from WHO noted that as many as 450 people may have been infected in the current outbreak. Officials have reported hot spots of the outbreak in Nigeria’s southern states of Edo, Ondo, and Ebonyi, with the Edo state seeing at least 85 of those laboratory-confirmed cases.

“The high number of Lassa fever cases is concerning. We are observing an unusually high number of cases for this time of year,” said Wondimagegnehu Alemu, MD, MPH, a WHO Representative to Nigeria. The outbreak has included 11 infected health care workers, 4 of whom have died. “Given the large number of states affected,” Dr. Alemu continued, “Many people will seek treatment in health facilities that are not appropriately prepared to care for Lassa fever patients and the risk of infection to health care workers is likely to increase.”

In response, the WHO has reported that 2845 people who have come into contact with infected patients are being monitored. In addition, the WHO is supporting the NCDC in surveillance, laboratory testing, clinical management of patients, and community engagement.

“The progress made so far to respond to the Lassa outbreak, including identification and monitoring of contacts to facilitate early referral for treatment and, would not have been possible without the technical and logistics support of WHO”, said Edo state health commissioner David Osifo in a recent statement.

To prevent the spread of Lassa fever, the WHO recommends washing hands regularly, storing food in sealed containers, cooking food thoroughly, keeping homes clean to deter rats, and keeping cats.