Lassa fever is a disease that remains a serious public health concern in Nigeria and other parts of West Africa. Although it has existed for decades, seasonal outbreaks continue to raise alarm due to their potential severity and high fatality rate when treatment is delayed.
According to the Nigeria Centre for Disease Control and Prevention (NCDC), Nigeria recorded a rise in Lassa fever activity in the first three weeks of 2026, with week 1 having 104 suspected cases and 21 confirmed cases, with 9 deaths reported.
Here are nine things to know about this deadly disease.
1. Lassa fever is a viral illness common in West Africa
Lassa fever, caused by the Lassa virus, is an acute viral hemorrhagic disease that is endemic in countries like Nigeria. Seasonal outbreaks occur every year, especially during the dry season when rodent exposure increases.
2. It is spread mainly by rats
The virus is carried by the multimammate rat. Humans become infected when they come into contact with food, surfaces, or household items contaminated by the rat’s urine or poop.
3. Person-to-person transmission is possible
Lassa fever can spread through contact with the bodily fluids of an infected person, particularly in healthcare settings without proper protective measures.
4. Early symptoms often look like common illnesses
Initial signs like fever, weakness, headache, sore throat, and nausea can mimic malaria or typhoid, which is why many cases are missed or treated late.
5. Some infections are mild, but others can be severe
While many people recover with mild symptoms, severe cases can lead to bleeding, breathing difficulty, organ failure, and even death if untreated.
6. Early treatment saves lives
The antiviral drug ribavirin is effective when given early. Prompt medical care greatly improves survival and reduces complications.
7. Hearing loss is a known complication
One complication of Lassa fever is that about 1 in 3 people who survive Lassa fever may experience temporary or permanent hearing loss, even in mild cases.
8. Rodent control is key to prevention
Keeping homes clean, storing food properly, sealing entry points, and improving sanitation significantly reduce the risk of infection.
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9. Healthcare workers face a higher risk
Without strict infection prevention practices, doctors and nurses are vulnerable when caring for infected patients. A doctor named Salome Oboyi in Plateau State died after contracting the viral infection while attending to an infected patient.