Navegando por Autor "Vianna, Manoella Campostrini Barreto"
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Item Prevalence of antibodies to spotted fever group rickettsiae in humans and domestic animals in a brazilian spotted fever−endemic area in the state of São Paulo, Brazil : serologic evidence for infection by Rickettsia rickettsii and another spotted fever group rickettsia.(2004) Horta, Maurício Cláudio; Labruna, Marcelo Bahia; Sangioni, Luis Antônio; Vianna, Manoella Campostrini Barreto; Gennari, Solange Maria; Galvão, Márcio Antônio Moreira; Mafra, Cláudio Lísias; Vidotto, Odilon; Schumaker, Teresinha T. S.; Walker, David HughesIn serum samples obtained from all the healthy humans, horses, dogs, and donkeys present on three farms in the Pedreira Municipality, an endemic area for Brazilian spotted fever, an indirect immunofluorescence assay (IFA) detected antibodies against Rickettsia rickettsii in 17 (77.3%) horses, 5 (31.3%) dogs (titers ranging from 64 to 4,048), and none of 4 donkeys or 50 humans. Five canine and eight equine sera with high antibody titers to R. rickettsii were also tested by IFA against R. bellii, R. akari, and R. africae antigens. Sera from two horses and two dogs that showed similar high antibody titers against two rickettsial antigens were evaluated after cross-absorption. Sera from seven horses and two dogs contained antibodies specific for R. rickettsii, and one dog serum had antibodies against a Rickettsia species very closely related to R. africae. The latter may have been caused by infection with the recently identified COOPERI strain.Item Rickettsial infection in animals and brazilian spotted fever endemicity.(2005) Sangioni, Luis Antônio; Horta, Maurício Cláudio; Vianna, Manoella Campostrini Barreto; Gennari, Solange Maria; Soares, Rodrigo Martins; Galvão, Márcio Antônio Moreira; Schumaker, Teresinha T. S.; Ferreira, Fernando; Vidotto, Odilon; Labruna, Marcelo BahiaWe compared the rickettsial infection status of Amblyomma cajennense ticks, humans, dogs, and horses in both Brazilian spotted fever (BSF)–endemic and –nonendemic areas in the state of São Paulo, Brazil. Most of the horses and few dogs from BSF-endemic areas had serologic titers against Rickettsia rickettsii antigens. In contrast, no dogs or horses from BSF-nonendemic areas had serologic titers against R. rickettsii antigens, although they were continually exposed to A. cajennense ticks. All human serum samples and ticks from both areas were negative by serologic assay and polymerase chain reaction, respectively. Our results indicate that surveys of horse serum are a useful method of BSF surveillance in areas where humans are exposed to A. cajennense ticks. In addition, we successfully performed experimental infection of A. cajennense ticks with R. parkeri.Item Rickettsial spotted fever in Capoeirão Village, Itabira, Minas Gerais, Brazil.(2008) Vianna, Manoella Campostrini Barreto; Horta, Maurício Cláudio; Sangioni, Luis Antônio; Cortez, Adriana; Soares, Rodrigo Martins; Mafra, Cláudio Lísias; Galvão, Márcio Antônio Moreira; Labruna, Marcelo Bahia; Gennari, Solange MariaThe present study investigated the infection by spotted fever rickettsia in an endemic area for Brazilian spotted fever (BSF; caused by Rickettsia rickettsii) in Minas Gerais State, Brazil. Human, canine and equine sera samples, and Amblyomma cajennense adult ticks collected in a rural area of Itabira City, Minas Gerais State were tested for rickettsial infection. Through Immunofluorescence Assay (IFA) we demonstrated the presence of antibodies anti-R. rickettsii in 8.2%, 81.3% and 100% of the human, canine and equine sera, respectively. None of the 356 tick specimens analyzed were positive for Rickettsia by the hemolymph test or Polymerase Chain Reaction technique (PCR) for the htrA and the gltA genes. Our serological results on horses and dogs (sentinels for BSF) appoint for the circulation of a SFG Rickettsia in the study area, however in a very low infection rate among the A. cajennense tick population.