Lassa fever in West Africa

Updated: June 22, 2016

Travel Health Notice

Lassa fever is caused by a virus carried by infected rats (rodents) in parts of West Africa. It is known to occur in Benin, Ghana, Guinea, Liberia, Mali, Sierra Leone, Nigeria as well as other West African countries. The disease causes outbreaks almost every year during certain peak times, usually between December and February. Urine or feces of infected rats are common sources of exposure to Lassa virus in humans. Rats often go unnoticed living in homes and areas where food is stored.  Lassa virus may also be spread between humans through direct contact with the blood, urine, feces or other bodily secretions of a person infected with Lassa fever. The disease typically includes symptoms such as fever, general weakness, headache, sore throat, although severe cases progress with symptoms of bleeding (for example: mouth or nose), facial swelling, pain in chest and shock. There is no vaccine or medication that protects against Lassa fever infection.

Outbreaks of Lassa fever are currently being reported in the West African countries of Liberia, Nigeria and Togo:

Liberia: Since January 2016, cases of Lassa fever have been reported in Liberia with the majority of cases in Bong and Nimba. Other affected counties include: Gbarpolu, Lofa, Margibi and Montserrado.

Nigeria: Since August 2015, cases of Lassa fever have been reported in several states in Nigeria. 

Togo: In March 2016, the Togo Ministry of Health started their outbreak investigation in response to the country's first two cases of Lassa fever infection which were reported in health care professionals. The affected area in Togo borders with Benin. 

For up to date information on affected areas in these countries, please visit the World Health Organisation Disease outbreak news on Lassa fever.

An outbreak of Lassa fever occurred in Benin between December 2015 and April 2016.  The Ministry of Health in Benin declared the end of Lassa fever transmission on May 23, 2016.

The Public Health Agency of Canada recommends that those travelling to Liberia, Nigeria and Togo practise usual precautions as outlined in the recommendations section below. Individuals most at risk include those living or working in affected areas, health care workers and others providing care for patients in the community.

Recommendations

Consult a health care provider or visit a travel health clinic at least six weeks before you travel.


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