diagnosis of leptospirosis in febrile patients of golestan province, iran: serology versus pcr

Introduction: leptospirosis is a significant public health problem in the caspian littoral of iran comprising gilan, mazandaran, and golestan provinces. in golestan province, serology assays indicated antileptospira antibodies in animals and humans; however, no reliable record of infections in patients with signs and symptoms of the disease is available. methods: we employed the indirect immunofluorescent antibody assay (ifa), and two pcr assays, a realtime pcr (qpcr) and a nestedpcr targeting 16s rdna (rrs) sequence for diagnosis of leptospirosis in febrile patients in golestan province. results: out of 52 febrile patients, 25 (48.07%) had antibody titers ge;1/80 by ifa, and were defined as positive. in 7, 9, and 7 individuals, the antibody titers were 1/40, 1/20, and 1/10, respectively, and 4 had no antibodies. the qpcr and nested pcr detected leptospiral dna in 55.75% and 67.3% of the patientschr('39') sera, respectively. the two pcr assays had a kappa agreement of 0.53 (p< 0.0001), suggesting a moderate agreement, and showed a significant reverse association with the ifa titers (p<0.05). conclusion: our results suggest that higher antibody titers accompanied the spirochetechr('39')s removal from blood by the patientchr('39')s immune response. hence, a reliable diagnosis of leptospira infection necessitates deploying a dnabased method alongside serology.