Banca de DEFESA: SIMONE DELGADO TOJAL

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : SIMONE DELGADO TOJAL
DATE: 30/08/2022
TIME: 15:00
LOCAL: Videoconferência
TITLE:

TICKS AND INFECTION BY RICKETTSIA OF THE SMOKED FEVER GROUP IN TICKS IN EASTERN ACRE STATE, WESTERN BRAZILIAN AMAZON

KEY WORDS:

Rickettsia amblyommatis, Rickettsia rhipicephali, Amblyomma latepunctatum, Haemaphysalis juxtakochi, Ixodidae

PAGES: 122
BIG AREA: Ciências da Saúde
AREA: Saúde Coletiva
SUMMARY:

A variety of rickettsial agents, infecting different species of ticks, has been reported in Brazil.
The Brazilian Amazon, despite its territorial extension and high diversity, presents timid records
regarding the composition of the ixodofauna and its infection by rickettsial agents. The state of
Acre, which is part of the Amazon region, has no recorded cases of Brazilian spotted fever, but
there is a report of the agent Rickettsia parkeri strain Atlantic Forest as the only record of a
pathogen infecting ticks in the Amazon. The aim of this study was to investigate Rickettsia
infection of the spotted fever group in ticks in eastern Acre state, Brazil. From July 2019 to
September 2021, Free-living ticks and parasitizing wild animals were collected in different
locations in the state. Free-living ticks were sampled using visual inspection and trawling
methods. As for ticks parasitizing wild animals, they were captured by traps (Pitfall, Tomahawk
and mist nets) and by third-party host collection and occasional host collection methods. The
ticks collected were identified by morphological analysis. Molecular analyzes were performed
for 401 bp amplification of the citrate synthase gene (gltA), present in all Rickettsia spp. and
subjected to a second test for amplifying a 532 bp fragment of the 190-kDa outer membrane
protein (OmpA) gene, restricted to Rickettsia spp. of the spotted fever group. Ticks also
submitted to protocols targeting a ≈460 bp fragment of the tick mitochondrial gene 16S rDNA.
Ixodidae tick species are reported Amblyomma coelebs, Amblyomma latepunctatum,
Amblyomma naponense, Amblyomma nodosum, Amblyomma oblongoguttatum, Amblyomma
ovale, Amblyomma pacae, Amblyomma scalpturatum, Haemaphysalis juxtakochi,
Rhipicephalus microplus and Amblyomma spp. larva, found free in the environment. Species A.
coelebs, Amblyomma humerale, Amblyomma longirostre, A. naponense, A. nodosum, A.
oblongoguttatum, A. ovale, A. pacae, Amblyomma rotundatum, A. scalpturatum, H. juxtakochi,
Ixodes luciae and Amblyomma spp. and Ixodes sp. immature ticks, were found feeding naturally
on Rhinella marina, Chelonoidis denticulatus, wild birds and mammals. In the study, the first
record of the A. latepunctatum and H. juxtakochi species in the state of Acre was made. New
associations between ixodids of the Amblyomma, Ixodes and Haemaphysalis genera, and of
wild birds and mammals species have been described. Only one known vector for Rocky
Mountain spotted fever, A. ovale species, was found free in the environment and parasitizing
the lowland “caraxué-da-várzea” bird (Tamnophilus debilis), this being the first record of the
parasite/host association between species. Amblyomma sp2 larva found in “mucura” (Didelphis
marsupialis), parasitizing wild animals in the state of Acre. Rickettsia amblyommatis should be
considered a potential human pathogen, since A. coelebs ticks often feed on humans in the
Amazon. Future studies involving an investigation of rickettsial infection in the human
population and wild and domestic reservoirs, as well as the investigation of other potentially
pathogenic agents in the Amazon, are essential to implement epidemiological surveillance
actions to prevent emerging diseases, transmitted by ticks of medical and veterinary interest.
Research in search of description of new tick species and new reports of species, including soft
ticks, are a priority in ixodofauna studies in the region of the state of Acre, especially in the
border region with Peru.

BANKING MEMBERS:
Externo à Instituição - HERMES RIBEIRO LUZ - UFMA
Externo à Instituição - MATIAS PABLO JUAN SZABÓ - UFU
Externo à Instituição - JÁDER DE OLIVEIRA - USP
Presidente - 066.589.338-80 - LUIS MARCELO ARANHA CAMARGO - USP
Externo à Instituição - SÉRGIO DE ALMEIDA BASANO