Diagnóstico molecular de Mycobacterium leprae no estado de Mato Grosso, Centro-Oeste, Brasil

Abstract

Mycobacterium leprae is a bacillus that causes leprosy, a chronic infectious disease, being hyperendemic, in the State of Mato Grosso, Brazil. In addition to humans, infections in wild animals have already been reported in the literature. Due to the high prevalence in humans and the lack of data on natural infection in animals, the aim of the research was to investigate M. leprae infection in free-living animals and the occurrence of genotypes based on variable numbers of polymorphism repeats (TTC) in humans. The polymerase chain reaction (PCR) was used using a pair of specific primers RLEP and TTC. Thus, DNA extraction occurred in 228 skin smear smear microscopy slides of human patients treated at the reference center for leprosy control in the Midwest region of Brazil, in 144 tissue samples (blood and spleen) belonging to 25 animal specimens free-living wild animals run over on the highways. And in 269 samples of spleen from small wild non-flying mammals, belonging to the order Didelphimorphia and Rondentia, from field expeditions in the Amazon and Cerrado biomes. All samples are from the State of Mato Grosso, Brazil. Thus, 18.8% (43/228) of the smear microscopy slides were positive. However, M. leprae was detected by PCR by the RLEP gene in 75.9% (173/228) of the slides. Of these positives, genotyping was performed with the TTC primer, amplifying 50.86% (88/173). The TTC genotypes found showed great variability of TTC11 17% (15/88) and TTC12 45.4% (40/88). Of the 25 specimens from wild animals that were run over, 44% (11/25) were positive in PCR-RLEP. In small wild non-flying mammals were positive by PCRRLEP in 13.75% (37/269) of the samples. According to these studies, based on the methodology used, we can conclude that the sensitivity of PCR-RLEP in relation to sputum smear microscopy is relatively superior, and that M. leprae genotypes showed variability in humans, thus indicating that these genotypes may be geographically related to the studied region. The free-living animals, Cavia aperea, Cerdocyon thirty, Chrysocyon brachyurus, Euphractus sexcinctus, Hydrochoerus hydrochaeris, Mazama gouazoubira, Mico melanurus, Nasua nasua, Puma concolor and Tamandua tetradactyla; and the non-flying wild mammals, Cryptonanus sp., Marmosa constantiae, Didelphis albiventris, Gracilinanus agilis, Proechimys roberti, Cerradomys sp., Neacomys sp., and Thrichomys pachyurus; may play an important role in the epidemiology of leprosy, which contributes to a Single Health view. Given the above, it is necessary to explore the findings in humans and animals described in this research for the future understanding of the correlation of these results in transmission between humans, animals and the environment.