Banca de DEFESA: AROLDO DE SOUZA JUNIOR

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : AROLDO DE SOUZA JUNIOR
DATE: 13/03/2026
TIME: 08:00
LOCAL: Videoconferência
TITLE:

Molecular characterization of Ehrlichia canis in naturally infected dogs from the microregion of Unaí, Minas Gerais, Brazil.

KEY WORDS:

intracellular bacterium, molecular biology, genetic diversity, p28, trp36.

PAGES: 46
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUBÁREA: Medicina Veterinária Preventiva
SPECIALTY: Doenças Parasitárias de Animais
SUMMARY:

Ehrlichia canis is a Gram-negative, obligate intracellular bacterium responsible for Canine Monocytic Ehrlichiosis (CME), whose transmission occurs through Rhipicephalus linnaei in Brazil. Its distribution has been described in all regions of the country. Studies involving E. canis have identified immunoreactive proteins that present species-specific antigens and are related to host–parasite interaction, providing relevant information about the genetic diversity of the pathogen. In this context, the present study aimed to analyze the prevalence and genetic diversity of E. canis, using the p28 and trp36 genes, in whole blood samples from naturally infected dogs from the microregion of Unaí, Minas Gerais. A total of 386 whole blood samples from dogs were analyzed using molecular techniques based on the p28 and trp36 genes. Among the analyzed samples, 3.1% (12/386) showed amplification for the p28 gene of E. canis. Among the samples positive for p28, 66.7% (8/12) amplified for the trp36 gene. For sequencing and genetic diversity analysis, 11 sequences of the p28 gene and five sequences of the trp36 gene were used. The sequences obtained for the p28 gene showed identity ranging from 99.27% to 100% when compared with E. canis sequences from different geographic regions and, in the amino acid translation analysis, mutation sites were observed. Haplotype network analysis based on the p28 gene revealed nine distinct haplotypes (Hd = 0.9632). For the trp36 gene, simultaneous circulation of American and Brazilian genotypes was observed in the studied region, demonstrating broad genetic diversity and local heterogeneity. It is concluded that E. canis strains circulating in dogs in the microregion of Unaí, Minas Gerais, present genetic diversity in the trp36 and p28 genes. The variation observed in tandem repeat regions and the presence of exclusive haplotypes demonstrate gene flow among strains. The co-circulation of BR and US genogroups reinforces the genetic complexity of the agent in the region and highlights the importance of continuous molecular monitoring.

COMMITTEE MEMBERS:
Presidente - 3247559 - BRUNA DE AZEVEDO BAETA
Externa à Instituição - ANA PAULA MARTINEZ DE ABREU - UV
Externa à Instituição - IZABELA MESQUITA ARAÚJO - UFRRJ
Externo à Instituição - JENEVALDO BARBOSA DA SILVA - UFVJM
Externo à Instituição - RENATA FERNANDES FEREIRA DE MORAES - UV