| dc.description.abstract | Owing to the importance of Amblyomma cajennense and Amblyomma dubitatum in the epidemiology of Brazilian Spotted Fever (BSF), this study evaluated the flutuation of populations of the free-living and parasitic these two species of the ticks, as well the frequency of ticks infection by Rickettsia spp. in Coronel Pacheco, risk area for occurrence of BSF in Minas Gerais State. Larvae of Amblyomma sp. were collected from pasture using the technique of drag sampling with flannelette during May to October 2006, from February to November 2007 and from March 2008. Well-defined peaks of populations occurred in May 2006, April-May 2007, April 2008 and October-November 2007. Larvae of A.cajennense were collected from animals during May to September 2006, from March to September 2007 and from April 2008. Well-defined peaks of populations occurred in May 2006, April-May 2007 and April 2008. Nymphs of Amblyomma sp. were captured from pasture throughout the year by the use of traps with carbon dioxide and peaks populations were observed between June and November, with an increase in population density in July and October-November 2006 and 2007. Nymphs of A. cajennense were captured throughout the year on equines and peaks populations were observed between June and November, with an increase in population density in July 2006 and 2007. Adults were captured from pasture throughout the year by the use of traps with carbon dioxide with an increase in population density from October to March and from August to April for A. cajennense and A. dubitatum, respectively, during the two years of experiment. Adults of A. cajennense occurred on animals throughout the year with an increase in population density from September to April. A total of 1213 ticks were individually processed by the hemolymph test with Gimenez staining and being all sample negative. By polimerase chain reaction (PCR) targeting a fragment of the rickettsial gene gltA only two adults A. cajennense ticks (one male and one female) and four pools of 5 nymphs showed the expected products. The DNA sequencing of two adults A. cajennense ticks showed 100% identity to the corresponding sequences of the R. rickettsii genes fragments gltA, OmpA and OmpB available in Gen Bank. The DNA sequencing of four pools of nymphs showed 99, 7% identity to the corresponding sequences of the Rickettsia tamurae genes fragments gltA available in Gen Bank. This results showed one more time molecular evidence for the presence of R. rickettsii in populations of A. cajennense in Coronel Pacheco and suggest the identification of R. tamurae in populations of A. cajennense and A. dubitatum | |
