Banca de DEFESA: KEITY KELLY VIANNA BENETTI

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : KEITY KELLY VIANNA BENETTI
DATE: 27/09/2023
TIME: 09:00
LOCAL: Plataforma zoom video
TITLE:

MOLECULAR SURVEY OF RICKETTSIA SPP AND MYCOBACTERIUM LEPRAE IN TICKS OF THE GENUS AMBLYOMMA KOCH, 1844 (ACARI: IXODIDAE) ASSOCIATED WITH SIX BANDED ARMADILLOS (EUPHRACTUS
SEXCINCTUS) CAPTURED IN THE STATE OF RIO GRANDE DO NORTE, BRASIL.

KEY WORDS:

molecular biology, acarology, coinfection, PCR-RFLP

PAGES: 105
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUBÁREA: Medicina Veterinária Preventiva
SPECIALTY: Doenças Parasitárias de Animais
SUMMARY:

The discovery of zoonotic transmission of Mycobacterium leprae by nine-banded armadillos
(Dasypusnovemcinctus) in the United States of America (USA) has challenged the prospects for
eradication of leprosy, and evidence is cumulating to support a similar role for Brazilian armadillos
including D. novemcinctus and the six-banded armadillo (Euphractus sexcinctus). Associations
between ticks of the genus Amblyomma and various species of armadillo have been recorded in Brazil.
Yet, few studies investigated the possible infection of ticks associated with armadillos for bacteria of
the genus Rickettsia and none evaluated the presence of M. leprae. Justification to perform such
investigations is provided by recent data implicating Rickettsia amblyommatis, infecting Amblyomma
pseudoconcolor (recovered from E. sexcinctus), as the probable etiologic agent of a spotted fever
outbreak in Pernambuco (PE), and by the observation that, after infection of adult female A. sculptum
ticks via artificial feeding, M. leprae cells persisted in the midgut and could be detected in the ovaries
of the ticks. In addition, the bacteria weredetected in the progeny (eggs and larvae),suggesting a role
for ticks as reservoirs and/or vectors of M. leprae. Thecurrent project examined 30 ticks recovered
from specimens of E. sexcinctus, known to be infected with M. leprae, collected in Rio Grande do
Norte (RN) and an additional 44 ticks collected from giant Armadillos (Priodontes maximus), in Mato
Grosso do Sul (MS). Ticks from RN were identified as Amblyomma auricularium (14 nymphs and 16
adults), based on sequencing of 16SrDNA and morphological characters, and samples from MS were
identified as Amblyomma sculptum (41 adults and 3 nymphs). DNA was extracted from ticks by
homogenization using a bead-beater apparatus, followed by phenol chloroform purification. DNA
wasexamined in a battery of polymerase chain reaction (PCR) assays, designed to amplify tick DNA
sequences (16SrDNA, COI and ITS2), sequences present in Rickettsia (htrA, ompA, ompB, sca1,
sca2, sca9, sca14, atpA and coxA). In addition, two assays used the RLEP sequence of M.leprae as
target. No evidence was found for the presence of M.leprae DNA in any of the 74 ticks examined.
Similarly, there was no evidencefor the presence of Rickettsia DNA in the A. sculptum ticks (n=44). In
contrast, 24/30 A. auricularium ticks were infected with at least one species of Rickettsia based on
data generated by PCR-restriction fragment length polymorphism (PCR-RFLP) and confirmed by
nucleotide sequencing. A total of 13 (44,3%) samples were classified as coinfected with R.
Amblyommatis and R. belli, a single tick (3,33%) was designated as co-infected with Rickettsia parkeri
(based solely on PCR-RFLP data) and R.bellii, 8 ticks (26,6 %) were infected soley with R. bellii and
the two remaining samples were classified as infected with R. amblyomattis. Sequence analysis of
ompA “amplicons “ showed the R. amblyommatis stains to be identical to each other and BLASTn
analysis showed them to have 100% nucleotide similarity with ompA sequences derived from strains
of R. amblyommatis identified in A. auricularium and A. pseudoconcolor ticks recovered from
specimens of E. sexcinctus inPernambuco.The absence of detectable levels of M. leprae DNA, in A.
auricularum recovered from specimens of E. Sexcinctus naturally infected with the pathogen,
indicated that transmission of M. Leprae to humans via ticks is improbable. The detection of
A.auricularium infected with R. amblyommatis and R. Bellii confirms previous observations.
However, the detection of co-infected specimens was inedited for this species of tick. In addition, the
presence of a possible co-infection with R.parkeri and R.bellii was an unprecedented finding. The
PCR-RFLP systems used herein provided an alternative, rapid and cost-efficient (relative to strategies
based on sequencing or real-time PCR), approach to evaluate co-infections (a potentially significant
phenomenon) that has most likely been underestimated to date.

COMMITTEE MEMBERS:
Presidente - 1354903 - DOUGLAS MCINTOSH
Interna - 3103528 - CLAUDIA BEZERRA DA SILVA
Interna - 1282902 - KATIA MARIA FAMADAS
Externo à Instituição - GILBERTO SALLES GAZÊTA - FIOCRUZ
Externo à Instituição - HERMES RIBEIRO LUZ - UFMA