Role of IgM specific indirect immunofluorescence assay in diagnosing an outbreak of leptospirosis

The study was conducted during a suspected epidemic of leptospirosis in Maharashtra. A total of 13 acute phase blood samples, collected at 5-6 days from the onset of symptoms, and 10 convalescent phase samples, colected at around 20 days from the onset of symptoms were obtained from 13 patients. Sera were separated and the samples were subjected to Microagglutination Test (MAT) and IgM-Indirect Immunofluorescence assay (IFA) to detect antibodies against leptospira. In the acute phase sera, only one sample was positive by MAT while seven were positive by IFA. In the convalescent samples, six were positive by MAT and seven were positive by IFA. IFA is a rapid test and can be used for early diagnosis of leptospirosis.