Natural environmental water sources in endemic regions of northeastern Brazil are potential reservoirs of viable Mycobacterium leprae

Abstract

BACKGROUNDThe detection of live Mycobacterium leprae in soil and animals other than humans suggests that the environment plays a role in the transmission of leprosy.OBJECTIVEThe objective of this study was to investigate the presence of viable M. leprae in natural water sources used by the local population in five municipalities in the state of Ceará, northeastern Brazil.METHODSSamples were collected from 30 different sources. Viable bacilli were identified by reverse transcriptase polymerase chain reaction (PCR) of the M. leprae gyrA gene and sequencing of the PCR products. Physicochemical properties of each water source were also assessed.FINDINGS M. leprae gyrA mRNA was found in 23 (76.7%) of the water sources. No association was found between depth of the water and sample positivity, nor was there any association between the type of water used by the population and sample positivity. An association between viable M. leprae and temperature and pH was found. Georeferencing showed a relation between the residences of leprosy cases and water source containing the bacterium.MAIN CONCLUSIONSThe finding of viable M. leprae in natural water sources associated with human contact suggests that the environment plays an important role in maintaining endemic leprosy in the study region.

Poor WASH (Water, Sanitation, and Hygiene) Conditions Are Associated with Leprosy in North Gondar, Ethiopia

“…However, experimentally based studies with mouse foot pad cultures do prove the survivability of M. leprae in soil and free-living amoeba [ 24 ]. Studies on environmental reservoirs of leprosy have relied primarily on reverse-transcriptase polymerase chain reaction (rt-PCR) of leprosy to assess reliability, and one study quantifying mRNA from M. leprae lends stronger support to the ability of these studies to assess viable bacteria in environmental samples [ 12 , 13 , 21 , 23 , 27 ].…”

Detection of Mycobacterium leprae DNA in soil: multiple needles in the haystack

“…Through PCR amplification of M . leprae DNA, its presence has been detected in environmental samples such as soil 11–16 and water 17,18 in areas inhabited by leprosy patients in Brazil and India. The viability of M .…”

Prevalence of Mycobacterium leprae in armadillos in Brazil: A systematic review and meta-analysis

“…A wide variety of contact with armadillos through hunting, cooking and consumption of armadillo meat was described among residents of the State of Ceará, in north-eastern Brazil [36]. The complexities of human-armadillo interaction in relation to M. leprae include the suggestion that transmission can occur in the opposite direction [29] and evidence that infection in armadillos is part of a wider environmental pool of M. leprae [37].…”