Infecção por Rickettsia em artrópodes vetores de uma região sob acentuada pressão antrópica no Vale do Rio Doce, Estado de Minas Gerais

• Autor(a) principal: Barros, Edvaldo
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2436
• topic: Rickettsia; Vale do Rio Doce; Artrópodes; Rickettsia; Rio Doce Valley; Arthropods; CNPQ::CIENCIAS BIOLOGICAS::BIOQUIMICA::BIOLOGIA MOLECULAR

The gender Rickettsia is constituted by alpha-protobacteria gramnegatives, pleomorphics and obligatory intracellular parasites that infect preferentially endothelial cells, transmitted to the vertebrate host through fleas, lices and, mainly, ticks. These microorganisms, thoroughly distributed by the world, are reported infecting ticks of almost whole national territory, however, with high concentration in the southeast area, been caused the diseases denominated Rickettsiosis. The Brazilian Spotted Fever (BSF), whose etiological agent is the Rickettsia rickettsii, is the most common in our country. The more common clinical signs of this illness are sudden fever, headache and myalgias, sometimes showing exanthemas, mainly in the members and area of the trunk. Most of the time, the symptoms are undifferentiated of other diseases, being very important the patient s epidemiologic characterization. In this context, this work had as major subject verifies by molecular investigation the occurrence of rickettsias in ticks collected in an endemic area for BSF under accentuated anthropic pressure due the construction of a hydroelectric enterprise near to pastures and fragments of Atlantic forest, in the limit between the municipality of Caratinga and Ipanema, in the worth of Rio Doce Valley, state of Minas Gerais, Brazil. Were collected 863 ticks of free live by the method of drags of white flannel and trap of CO2 and 90 ticks sponging domestic (horses and dogs) animals. These ticks were identified through taxonomic keys and processed for the extraction of the genomic DNA. Purified DNA was tested through the nested-PCR for the presence of organisms with the use of genderspecific primers. The ticks in the studied region were Amblyomma spp., A. cajennense, Dermacentor nitens, Rhipicephalus microplus and R. sanguineus, being observed the prevalence of ticks of the gender Amblyomma (94.6%). The species of ticks in relationship of parasitism with domestic animals most prevalent were A. cajennense (41.1%) followed by R. sanguineus (34.4%). Rickettsia spp. was detected infecting ticks of several lots, been only one relative to the ticks of free life and the remnant of the ticks in parasitism relationship. The frequency of infection by rickettsias in A. cajennense, D. nitens, R. microplus and R. sanguineus, were of 2.27%, 12.5%, 16.67% and 6.45%, respectable. These results associated to the evidence of the reemergence of suspects cases of BSF in the region, suggest the occurrence of Rickettsiae organisms circulating in the studying area evidencing the needing of more molecular and serological studies to better understanding the role of domestics and wild animals in the epidemiology of the rickettsiosis and its vectors arthropods, with special attention due subjects the considerable levels of anthropic pressure, associated to a high level of environmental interference, with consequently change of ecosystems.