Biodiversidade de potenciais vetores de rickettsias em áreas de vulnerabilidade para febre maculosa no município de Juiz de Fora, Minas Gerais, Brasil

Abstract

The city of Juiz de Fora, in the Brazilian state of Minas Gerais, stands out in the epidemiologic context for possessing vulnerability indicators, such as a high number of this state´s notifications, with cases occurring in the urban perimeter, which contains an elevated population density, and the occupation of limit areas with forests´ fragments, which have a frontier with confirmed endemic areas, making possible the interchange of arthropod vectors with mammal hosts. Such areas propitiate the development and the maintenance of the enzootic and the epidemic cycles for the Spotted Fever. By the above, the general objective of this project was to investigate and to map the natural relation between Rickettsia sp. Species and its potential vectors in five regions of vulnerability in the city. Specifically, here are the objectives: the determination of the fauna composition for ectoparasites potentially vectors, collected on vertebrate hosts, as well as loose in the environment; analysis of the enzootic cycle through the detection of rickettsias by Polymerase Chain Reaction (PCR); the rickettsias agents characterization through sequencing and phylogenetic analyses and the evaluation of the epidemiologic aspects of the circulating rickettsias, of the vectors and their vertebrate hosts. The ectoparasites were collected in the period of 2013-2014 in places that need information on the maintenance of rickettsias transmission cycle: Caetés, Igrejinha, Paula Lima, Torreões e Valadares. As a total, there were collected and identified 12,692 ectoparasites, among fleas from the gender Ctenocephalides and ticks from the genders Amblyomma, Rhipicephalus and Dermacentor, with a posterior processing of 2,379 specimens in an individual way or gathered in lots according to place, sex, development state, constituting 249 samples. The genomic DNA from these samples was extracted and submitted to research of rickettsiais gltA (gênero Rickettsia) e ompA (Grupo da Febre Maculosa-GFM) genes. There were obtained 29 positive samples, except for Caetés; from which 16 for the gltA gene, with 11 sequenced samples, and 13 samples for the ompA gene, with seven sequenced; especially Amblyomma cajennense as the most prevalent species and with 4.29% of minimal infection rate. Sequences with 99 and 100% of identity with the pathogenic species Rickettsia felis were diagnosed in Ctenocephalides canis and Ctenocephalides felis. And in a surprising way the register of Rickettsia bellii in Amblyomma dubitatum in Juiz de Fora´s Micro-region, presenting sequences with 97% of homology. This paper reveals a bigger geographic distribution of rickettsias from GFM, including R. felis that causes rickettsiosis felis, in Juiz de Fora´s Micro-region.