Lassa high risk areas are near the western and eastern extremes of West Africa. As of 2018, the Lassa belt includes Guinea, Nigeria, Sierra Leone and Liberia.[6] As of 2003, 10-16% of people in Sierra Leone and Liberia admitted to hospital had the virus.[9] The case fatality rate for those who are hospitalized for the disease is about 15-20%. Research in showed a twofold increase risk of infection for those living in close proximity to someone with infection symptoms within the last year. The high risk areas areas cannot be well defined by any known biogeographical or environmental breaks except for the multimammate rat, particularly Guinea (Kindia, Faranah and Nzerekore regions), Liberia (mostly in Lofa, Bong, and Nimba counties), Nigeria (everywhere) and Sierra Leone (typically from Kenema and Kailahun districts). It is less common in the Central African Republic, Mali, Senegal and other nearby countries, and less common yet in Ghana and the Democratic Republic of the Congo. Benin had its ...