RESUMO
AIM: To characterize persistence of the causative agent in the blood of patients with leptospirosis, to evaluate significance of the results of polymerase chain reaction (PCR) with isolation of ribosomal RNA (rRNA) and microagglutination reaction (MAR) in diagnosis of leptospirosis at different stages of the disease. MATERIAL AND METHODS: The study included 94 patients with leptospirosis: 51 (54.2%) males, 43 (45.8%) females, 74 (78. 7%) urban and 20 (21.3%) rural citizens in acute leptospirosis, early and late convalescence. Leptospirosis was diagnosed on the basis of clinico-epidemiological, laboratory-device data. All the patients were divided into 2 groups: with leptospiral jaundice (n = 33, 35.1%) and without leptospiral jaundice (n = 61, 64.9%). The disease of moderate severity was in 64 (68%) patients. Verification of the diagnosis was based on determination of specific antibodies titer in MAR using standard set of diagnostic cultures. PCR determined rRNA of leptospira in the blood on the disease day 5, 10 and 15, 1, 2, 3, 6 and 12 months after the disease onset. The results were processed with methods of parametric and non-parametric statistics. CONCLUSION: PCR demonstrated diagnostic value in early leptospirosis (sensitivity of the method in the disease week 1 was 86%). Diagnostic significance of MAR reached 81.8% later - in 3 weeks. Detection of leptospiral rRNA by PCR in the autopsy material allows one to recommend this method for additional verification of the diagnosis including as an alternative to bacterioscopic test.