Banca de DEFESA: ANGÉLICA LORENA PEREIRA MENDES CARIOCA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : ANGÉLICA LORENA PEREIRA MENDES CARIOCA
DATE: 30/04/2024
TIME: 14:30
LOCAL: Sala Virtual Remota - https://bit.ly/DefMS_AngelicaCarioca_PGBIOEXP
TITLE:

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KEY WORDS:

nested–PCR, Borreliosis, Ehrliquiosis, Rondônia

PAGES: 74
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

Ticks are obligatory ectoparasites of vertebrate animals, which could accidentally parasitize humans. In Brazil, only rickettsiae are known to cause illness to humans, however, there are lack of studies about other pathogens in this country, such as the bacteria Borrelia and Ehrlichia, especially in the Amazon region, where there are a great number of anthropophilic tick species. The Borrelia genus are spirochaete bacteria that infect mammals and birds worldwide, and some species can cause the human Lyme disease. There are recent records of Borrelia-infected ticks in Brazil, but the occurrence of any human borreliosis still lack of evidence, although cases of a Lyme-like have been reported. The relapsing fever is a zoonosis also provoked by Borrelia spirochaetes that are associated to argasid ticks from the Ornithodoros genus. Ehrlichia spp. is a genus of obligatory intracellular Gram-negative bacteria that infect phagocytes of humans and animals. Ehrlichia chaffeensis and Ehrlichia ewingii are etiological agents of, respectively, monocytic and granulocytic ehrlichiosis in North America. This study aimed to survey the incidence of Borrelia spp. and Ehrlichia spp. infecting freeliving and parasitic ticks in the region of the Porto Velho Natural Park (PVNP), Rondônia state. The collection of free-living and wild animals parasitic ticks were performed within trails in the forest area of the PVNP, whereas the ticks collections from domestic animals (dogs and horses) were performed in private properties in the surrounding areas of the Park. After collected, the ticks were identified and submitted to DNA extraction and nested-PCR to search for borrelial Flab gene DNA, and semi nested-PCR targeting ehrlichial dsb gene DNA. The PCR products were visualized in a 1.5% agarose gel. A total of 153 free-living ticks were collected and the most abundant species were Amblyomma scalpturatum, followed by Amblyomma sp., A. naponense and Amblyomma calcaratum. Regarding the method of collection, 70% of the ticks were collected by dragging, 18% by dragg-flagging and 12% by visual inspection. An infection rate of 4.6% of Ehrlichia canis was found in Rhipicephalus linnaei. The infection rates of E. canis were 2% in Amblyomma scalpturatum and 1% in Dermacentor nitens. The positive samples were confirmed to the ehrlichial species by DNA sequencing of dsb gene partial sequence. There were no Flab gene fragment detection in the tested ticks, suggesting that there were no borrelial infection in the ticks. Although Ehrlichia infection have been reported in horses, the present study reports E. canis in D. nitens parasitizing horses for the first time. This study is the first to report E. canis in A. scalpturatum. The results of this study indicate that non-native pathogens may be introduced to the wild tick fauna in Brazil, and could help in a better understanding of the tick-pathogen-host relationships in the Western Amazon Region.

COMMITTEE MEMBERS:
Externa à Instituição - ALEXSSANDRA RODRIGUES DE MEDONÇA FAVACHO - FIOCRUZ
Presidente - ***.495.134-** - JANSEN FERNANDES MEDEIROS - UNIR
Externo à Instituição - THIAGO FERNANDES MARTINS - USP