Author(s): McCormick JB, Webb PA, Krebs JW, Johnson KM, Smith ES
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Abstract In studies of Lassa fever in Sierra Leone, the prevalence of human antibody to Lassa virus ranged from 8\% to 52\%. Mastomys natalensis, the reservoir of Lassa virus, constituted 50\%-60\% of the rodents captured in houses but only 10\%-20\% of those captured in surrounding agriculture and bush areas (chi 2 = 90.2, P less than 10(-6), df = 1), a finding suggesting that houses are the most-important location for transmission of Lassa virus. Viral infection of Mastomys from houses ranged from 0\% to 80\%. The incidence of seroconversions in susceptible persons ranged from 5\% to 22\% per year; the ratio of illness to infection ranged from 9\% to 26\%, and the proportion of febrile illness associated with seroconversion was 5\%-14\%. Eightfold rises in titer of antibody occurred in 1\%-18\% of the antibody-positive population, a result suggesting reinfection. We estimate the ratio of fatalities to infection to be 1\%-2\%, a rate lower than estimates based on hospitalized cases. The high incidence of Lassa fever makes it a major problem in West Africa.
This article was published in J Infect Dis
and referenced in Journal of Antivirals & Antiretrovirals