Distribution and persistence of Mycobacterium leprae nasal carriage among a population in which leprosy is endemic in Indonesia

Abstract

In order to understand better the relationship among Mycobacterium leprae, its transmission and the human host or the chain of infection which may lead to the development of leprosy, we performed a population survey in which nasal carriage of M. leprae was determined by a specific polymerase chain reaction (PCR), 2 years after an earlier survey in the same population. 1923 persons were registered, 1171 were clinically examined for signs of leprosy, and 418 were tested by PCR. The detection rate of leprosy in the study area had not changed significantly during the 2 years' observation period since the introduction of multi-drug therapy, i.e. 6/1000 compared to 7.7/1000 2 years before. Of 6 newly detected cases, 5 were diagnosed as having paucibacillary leprosy. The presence of M. leprae could be demonstrated by PCR in 2.9% (12/418) of the persons. PCR positivity was not persistent over the 2 years. All the PCR positive persons identified in the first survey were negative in the second, indicating that M. leprae nasal carriage is transient. As in the previous survey, we found evidence for widespread M. leprae nasal carriage as determined by PCR among the general population in an area in which leprosy is endemic. In addition, our data indicated that PCR positivity can occur in certain clusters in the community. This clustering seems to be time-dependent, not necessarily related to the presence of patients.

Unveiling healthy carriers and subclinical infections among household contacts of leprosy patients who play potential roles in the disease chain of transmission

“…However, they may spread M. leprae to susceptible individuals and this may be a plausible mode of transmission. Our results also corroborate previous studies that have detected M. leprae DNA in the nasal mucosa of endemic populations (Hatta et al 1995, Beyene et al 2003, Martinez et al 2011, regardless of the OC and CFs of their ICs. Our results revealed a linear correlation between bacillary DNA levels and the CFs of the patients' diseases.…”

“…The anti-PGL-I serology was strongly correlated with the MB OC and associated CFs of leprosy, indicating a possible active infection, as shown elsewhere (Cho et al 2001, Martinez et al 2011. However, the presence of M. leprae DNA in nasal swabs has been used as an epidemiological tool to understand the role of both patients and contacts in the complex transmission chain (Hatta et al 1995, Beyene et al 2003, Patrocínio et al 2005, Job et al 2008.…”

“…Because M. leprae is an obligate intracellular pathogen and there is little evidence of non-human reservoirs in endemic countries, it is most likely that leprosy spreads from person to person. Healthy carriers and people with subclinical infection have been recognised as links in the chain of M. leprae transmission (Hatta et al 1995, Beyene et al 2003.…”

ML0405 and ML2331 Are Antigens ofMycobacterium lepraewith Potential for Diagnosis of Leprosy

“…This suggests that active transmission of M. leprae is still occurring, but the route and mechanism of this transmission is still unclear. Household contacts of individuals with MB disease have a higher risk of developing clinical leprosy than those of paucibacillary patients (7,32), and this has been attributed to increased shedding of viable bacteria by MB patients (10,26). Diagnosis of leprosy at early stages and subsequent treatment would prevent disability and may also help reduce transmission.…”

Tendências temporais, distribuição espacial e fatores associados à ocorrência de hanseníase no Brasil, 2001 a 2012

“…A principal via de transmissão conhecida é de pessoa para pessoa, por meio de dispersão de gotículas nasal e bucal, especialmente entre os contatos domiciliares de pacientes multibacilares (MB) sem tratamento (Hatta et al,1995;Rodrigues e Lockwood, 2011;Cabral-Miranda et al, 2014). A transmissão da doença pelo meio ambiente não está clara.…”