What is it?
Lassa fever is an acute viral haemorrhagic illness caused by Lassa virus, a member of the arena-virus Family of viruses. It was discovered in 1969 and is named after the town in Nigeria where the first cases occurred.
How does it infect humans?
- Humans usually become infected with Lassa virus through exposure to food or household items contaminated with urine or faeces of infected Mastomys rats.
- Person-to-person infections and laboratory transmission can also occur, particularly in health care settings in the absence of adequate infection prevention and control measures.
Areas where Lassa Fever is endemic are:
- The disease is endemic in the rodent population in parts of West Africa.
- It is known to be endemic in Benin, Ghana, Guinea, Liberia, Mali, Sierra Leone, Togo and Nigeria
Other key facts about the fever
- The overall case-fatality rate is 1%. Among patients who are hospitalized with the severe clinical presentation of Lassa fever, case-fatality is estimated at around 15%. Early supportive care with rehydration and symptomatic treatment improves survival.
- About 80% of people who become infected with Lassa virus have no symptoms. 1 in 5 infections result in severe disease, where the virus affects several organs such as the liver, spleen and kidneys.
