RESUMO
Leptospirosis is a zoonotic disease caused by the genus Leptospira, presenting complex and dynamic epidemiology. To determine the genetic variability and its phylogenetic relationship of Leptospira spp isolates from three sources in Iquitos (Peruvian Amazon) from 2002 to 2013, seven MLST genes were analyzed to obtain the Sequence Type (ST) and these sequences were concatenated for phylogenetic analysis. The genetic relationship between STs was determined with the goeBURST algorithm and genetic diversity was determined using DnaSP. Of 51 isolates, 48 were pathogenic belonging to five different species: Leptospira interrogans Nascimento 2004, Leptospira santarosai Feil 2004, Leptospira noguchii Haake 2021, Leptospira borgpetersenii Levett 2021, and Leptospira kirschneri Levett 2021. Of 20 STs identified, 60% corresponded to new genotypes circulating only in Peru. The genotypes ST17, ST37, and ST301 were recorded in rodents and humans. A high intraspecific genetic diversity was demonstrated in L. noguchi. The goeBURST analysis revealed three clonal complexes (CCs) and 16 singletons. The STs were found to show high genetic variability and phylogenetic and goeBURST analysis determined that the genotypes found did not form specific groups according to the source of infection or origin, which confirms the zoonotic potential of these STs in an area highly endemic for leptospirosis.
RESUMO
BACKGROUND: Pulmonary involvement in leptospirosis remains poorly recognized in regions where it is endemic, despite reports of recent outbreaks and epidemic disease. METHODS: A prospective, population-based study was carried out to identify febrile patients exposed to Leptospira in urban and rural contexts in Iquitos, Peru. Evidence of exposure to Leptospira was obtained by serologic testing, and diagnosis of leptospirosis was confirmed in pulmonary cases by culture or quantitative real-time PCR assay. RESULTS: Of 633 consecutively enrolled febrile patients, 321 (50.7%) had antileptospiral IgM antibodies or high titers of antileptospiral antibodies. Seven patients with histories of only urban exposure to leptospires had severe pulmonary manifestations; of these, 5 patients died; 4 of the deaths were caused by pulmonary hemorrhage, and 1 was caused by acute respiratory distress syndrome and multiorgan failure. Real-time, quantitative PCR assay showed high levels of leptospiremia (>or=10(4) leptospires/mL) in most fatal cases; 1 patient, from whom tissue specimens were obtained at autopsy, had >or=10(5) leptospires/g of lung, kidney, and muscle tissue. DISCUSSION. This study demonstrates the underdiagnosis of leptospirosis in a region of high endemicity and the underrecognition of grave pulmonary complications. Pulmonary involvement in leptospirosis was present in urban but not rural areas. Presumptive treatment for leptospirosis should be initiated immediately in the appropriate epidemiological and clinical context.
