Figure 5.

Monthly distribution of suspected LF cases by serostatus. Month of clinical presentation was determined according to the date the initial ELISA Ag and IgM tests were performed. (a) Acute Lassa fever exposure (Ag+), (b) Recent Lassa fever exposure (Ag−/IgM+); (c) Non-Lassa fever cases or prior Lassa fever exposure (Ag−/IgM−). All tests were for suspected LF cases defined according to its suspected case definition. The blue-shaded regions represent the seasonal rainfall period in Sierra Leone (May to October).