Abstract | BACKGROUND: Early diagnosis, prompt treatment, and disease containment are vital measures in the management of Lassa fever (LF), a lethal and contagious arenaviral hemorrhagic disease prevalent in West Africa. Lassa Virus (LAV)-specific Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) test, the gold standard for diagnosis, is unavailable in most centers. Serologic detection of LAV IgM is a more accessible tool and this work was to investigate its adequacy as an early marker for LF. PATIENTS AND METHODS: A prospective case-control study conducted July 2007-March 2011 in a tertiary referral health center in Nigeria. Blood samples for test and control were evaluated for Lassa specific antigens and IgM using RT-PCR (primers S36+ and LVS 339) and indirect ELISA (Lassa Nucleo- protein (NP)- Antigen) respectively. RT-PCR outcome was used as standard to test for the sensitivity and specificity of IgM. RESULTS: Of the 37 confirmed cases of LF infection by RT-PCR, 21 (57%) were IgM positive. Amongst the 35 confirmed negative cases (control group), eight were IgM positive. The diagnostic sensitivity and specificity of the IgM assay were 57% and 77% respectively. The negative and positive predictive values of the IgM serological assay were 63% and 72%, respectively, while the efficiency of the test was 67%. CONCLUSION: The specificity and sensitivity of IgM as a screening tool for early detection of LF appear weak and, hence, the need for a reliable LF "rapid screening kit" since RT-PCR is unavailable in most centers. In the interim, "high clinical index of suspicion," irrespective of IgM status, requires urgent referral to confirmatory centers.
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Authors | Titus S Ibekwe, Maxwell M Nwegbu, Daniel Asogun, Donatus I Adomeh, Peter O Okokhere |
Journal | Nigerian medical journal : journal of the Nigeria Medical Association
(Niger Med J)
Vol. 53
Issue 4
Pg. 196-9
(Oct 2012)
ISSN: 0300-1652 [Print] Nigeria |
PMID | 23661877
(Publication Type: Journal Article)
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