Lassa Fever

What is Lassa Fever?

Lassa Fever is an acute viral illness caused by Lassa virus. The disease is endemic in west African countries of Guinea, Liberia, Sierra Leone and Nigeria. The virus reservoir is the wild rodent in west Africa. When humans get infected, the consequences range widely in severity, from asymptomatic infection without illness to extremely severe illness which may have a fatal outcome.

Incubation period is 6 to 21 days. The patient usually presents with fever, malaise, headache, sore throat, cough, nausea, vomiting, diarrhoea, myalgia, chest and abdominal pain. Inflammation of the throat with white tonsillar patches is an important distinguishing feature. The death rate is about 15%.

How does it spread?

Disease transmission is primarily through aerosol or direct contact with the excreta of infected rodents. Person-to-person spread may occur during the acute phase of 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.

  • on return, if fevers of unknown origin develop, one should seek prompt medical advice, informing doctor the recent travel history to Lassa Fever endemic areas so as to facilitate diagnosis.

How is it treated?

Specific treatment with intravenous injection of anti-viral drug may be effective if given within the first six days of illness.



Last revision date: 10 October 2012