Banca de DEFESA: JESSICA DA SILVA FERREIRA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : JESSICA DA SILVA FERREIRA
DATA : 09/05/2019
HORA: 13:00
LOCAL: SALA 14
TÍTULO:

Investigation of the possibility of zoonotic transmission of leprosy between armadillos and humans through molecular tools

PALAVRAS-CHAVES:

Mycobacterium leprae; armadillo; imunodiagnostics; genotyping; zoonose;

PÁGINAS: 170
GRANDE ÁREA: Ciências Agrárias
ÁREA: Medicina Veterinária
RESUMO:

Leprosy is a chronic and infectious disease with a high potential for causing physical disability. Until recently, it was believed that Mycobaterium leprae was an exclusively human pathogen. However, the detection of non-human sources of the bacterium, most notably in armadillos, raised questions about the transmission chain of leprosy. Armadillos of the species Dasypus novemcinctus are known to be involved in the maintenance and transmission of M. leprae to humans in the United States of America (USA), where leprosy is classified as a zoonotic disease. In Brazil, armadillos (principally D. novemcinctus) naturally infected by M. leprae have been reported in some regions. In addition, contact via hunting, handling, breeding and consumption of armadillo meat are considered a risk factor for transmission of the disease to humans. Yet, in contrast to the conclusive data presented by in the USA, evidence to support the existence of zoonotic leprosy, involving armadillos, in Brazil is essentially suggestive. The current study evaluated twenty specimens of the six-banded armadillo (Euphractus sexcinctus), collected from rural locations in the state of Rio Grande do Notre (RN), Brazil for evidence of infection with M. leprae. Serum was examined using two “in-house” enzyme-linked immunosorbent assays (ELISAs) and via two commercially available (ML flow and NDO-LID^®) immunochromatographic lateral flow (LF) tests, for detection of the PGL-I and/or LID-1 antigens of the bacterium. The presence of M. leprae DNA in liver tissue was examined using the M. leprae-specific repetitive element (RLEP), as target in conventional and nested PCR assays. Molecular and anti-PGL-1-ELISA data indicated that 20/20 (100%) of the armadillos were infected with M. leprae. The corresponding detection levels, recorded with the LF tests were 17/20 (85%) and 16/20 (80%), for the NDO-LID^® and ML flow tests respectively. Genotyping of human samples of M. leprae generated from patients in Mossoró, (RN), was conducted using systems based on Single Nucleotide Polymorphisms (SNPs) and Variable Number of Tandem Repeats (VNTRs) molecular markers. Those profiles were combined with the findings of other Brazilian and international studies, including those from armadillos in the USA, to generate a database. Analyses, based on VNTRs, of the M. leprae samples from E. sexcinctus showed them to be highly related to each other. However, a comprehensive analysis of all samples was not possible due to difficulties encountered in the amplification of some markers. Comparative analysis of the E. sexcinctus samples (n=7), containing the largest number of markers, with the profiles contained in the VNTR database did not provide definitive evidence for a common human /Brazilian armadillo genetic profile. However, given the deficiencies in the profiles of both the armadillo samples and a substantial portion of the human isolates, it would be incorrect to affirm that our data provided conclusive evidence against the existence of such a common profile in Brazil. It is recommended that, to resolve this uncertainty, improvements in the existing VNTR protocols should be made a priority for future research on this important topic.  Despite the inconclusive nature of the genotyping data, it was concluded that, in common with D. novemcinctus, six banded armadillos represent a potential reservoir of M. leprae and as such, their role in a possible zoonotic cycle of leprosy within Brazil warrants further investigation.

MEMBROS DA BANCA:
Externo à Instituição - ANDRE LUIZ RODRIGUES ROQUE - FIOCRUZ
Externo ao Programa - 1930226 - CARLOS ALEXANDRE REY MATIAS
Interno - 387340 - CARLOS WILSON GOMES LOPES
Presidente - 1354903 - DOUGLAS MCINTOSH
Externo à Instituição - HARRISON MAGDINIER GOMES - FIOCRUZ
Externo à Instituição - MARIA CRISTINA VIDAL PESSOLANI - FIOCRUZ
Externo ao Programa - 2688704 - TIAGO MARQUES DOS SANTOS