Lassa fever (LF) is a viral hemorrhagic fever (VHF) endemic to West Africa.1 Clinical presentation can range from asymptomatic or mildly symptomatic infection to severe illness; symptoms can include fever, chills, malaise, headache, myalgias, nausea, vomiting, and diarrhea.2–5 Hemorrhagic symptoms occur among a minority of patients.5 The overall case-fatality rate (CFR) was previously estimated to be 1–3%, with a higher rate for hospitalized patients (∼16%).2,4,5 Recent studies, however, have suggested CFR of almost 70% among patients with LF who were antigenemic at time of diagnosis.6 No LF vaccine exists.7 Treatment includes supportive care and the antiviral agent ribavirin.8 The LF reservoir host is Mastomys spp. rodents2,9; infection occurs primarily through contact with infectious rodent excreta.5 Secondary person-to-person transmission of LF, including nosocomial transmission, can occur through contact with infectious blood or body fluids.5 The LF incubation period lasts up to 3 weeks.4
Since the discovery of Lassa virus (LASV) in 1969,10 a total of seven LF cases diagnosed in the United States have been reported among travelers from West Africa.11–13 We describe here the clinical presentation of the eighth case, laboratory methods used for diagnosis, infection control protocols used, and public health response.
The authors thank medical staff and local, state, and federal public health personnel who assisted with this investigation. We also thank the laboratory personnel at the CDC Viral Special Pathogens Branch for specialized testing and Barbara Montana (New Jersey Department of Health) and Michael Gronostaj (Centers for Disease Control and Prevention) for manuscript review.
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