The Lassa Virus (an Arenavirus) is found in West Africa, where it sometimes a severe hemorrhage illness called Lassa fever.
The antivirus drug ribavirin is effective, but only if administered early in the course of illness. Because of its expense, need for
intravenous administration, potential toxicity, and teratogenicity, empiric therapy with ribavirin is undesirable. Laboratory
diagnosis of acute Lassa virus infection has traditionally employed the indirect fluorescent-antibody (IFA) test. However, enzymelinked
immunosorbent assays (ELISAs) for Lassa virus antigen and immunoglobin M (IgM and IgG) antibodies have been developed
that are thought to be more sensitive and specific likely represent underestimates with. The high sensitive and specificity, capability
for early diagnosis, and prognostic value of the ELISAs make them the diagnostic tests of choice for detection of Lassa fever.