Travel Health Service Lassa Fever
Travel related diseases

Lassa Fever

What is Lassa Fever?

Lassa Fever is an acute viral illness caused by Lassa virus. The disease is endemic in Benin, Ghana, Guinea, Liberia, Mali, Sierra Leone, and Nigeria, but probably exists in other West African countries as well. The virus reservoir is a wild rodent.

Incubation period is 6 to 21 days. The patient usually presents gradually with fever, malaise, headache, sore throat, cough, nausea, vomiting, diarrhoea, chest and abdominal pain. In severe cases facial swelling, fluid in the lung cavity, bleeding from the mouth, nose, or gastrointestinal tract. Shock, seizures, tremor, disorientation, and coma may be seen in the later stages. Deafness occurs in 25% of patients who survive the disease. Death usually occurs within 14 days of onset in fatal cases.

How does it spread?

Humans usually become infected with Lassa virus from exposure to urine or faeces of infected rodents. Lassa virus may also be spread between humans through direct contact with the blood, urine, faeces, or other bodily secretions of a person infected with Lassa fever.

How can you prevent it?

There is no vaccine available for Lassa Fever. Travellers to endemic areas have to observe good personal hygiene to minimize the risk of contracting Lassa Fever and adopt the following precautions:-

  • Avoid visiting or sleeping in places of poor environmental hygiene.

  • Do not have contact with sick rodents.

  • Do not contact person with fever.

  • If any symptoms develop on return, one should seek prompt medical advice and inform the doctor of recent travel history to Lassa Fever endemic areas.

How is it treated?

The antiviral drug ribavirin seems to be an effective treatment for Lassa fever if given early on in the course of clinical illness. There is no evidence to support the role of ribavirin as post-exposure prophylactic treatment for Lassa fever.