Novos relatos de carrapatos infectados por Rickettsia bellii no Brasil

This study investigated the occurrence of rickettsial infection in ticks collected from wild animals in two areas of Brazil. Amblyomma dubitatum ticks were collected from a capybara (Hydrochoerus hydrochaeris) in Guarda-Mor municipality, state of Minas Gerais, and Amblyomma pseudoconcolor ticks were collected from a six-banded armadillo (Euphractus sexcinctus) in Corumbá municipality, state of Mato Grosso do Sul. Attempts to isolate rickettsia in Vero cell culture were performed with one A. dubitatum tick and one A. pseudoconcolor tick, which were previously shown by the hemolymph test to contain Rickettsia-like structures within their hemocytes. Rickettsiae were successfully isolated in Vero cell culture from the two tick species. The two isolates were identified as Rickettsia bellii, since gltA partial sequences were 99.9%-100% identical to corresponding sequences of R. bellii in GenBank. While there have been several previous reports of R. bellii infecting A. dubitatum ticks, we provide the first report for A. pseudoconcolor, which increases to 25 the number of R. bellii-infected tick species in the American continent.O presente trabalho investigou a ocorrência de infecção por Rickettsia em carrapatos coletados em animais selvagens de duas áreas do Brasil. Carrapatos da espécie Amblyomma dubitatum foram coletados de uma capivara (Hydrochoerus hydrochaeris) no município de Guarda-Mor, Minas Gerais, enquanto exemplares da espécie Amblyomma pseudoconcolor foram coletados de um tatu-peba (Euphractus sexcinctus) do município de Corumbá, Mato Grosso do Sul. Tentativas para isolar Rickettsia em cultura de células Vero foram realizadas com um exemplar de A. dubitatum e um de A. pseudoconcolor, que foram previamente positivos no teste de hemolinfa com estruturas semelhantes a Rickettsia visualizadas em seus hemócitos. Rickettsia foram isoladas com sucesso em culturas de células Vero a partir das duas espécies de carrapatos. Os dois isolados foram identificados como Rickettsia bellii, uma vez que suas sequências parciais do gene gltA foram 99,9-100%, idênticas a sequências de R. bellii do GenBank. Embora haja vários relatos anteriores de R. bellii infectando A. dubitatum, este é o primeiro relato em A. pseudoconcolor, aumentando para 25 o número de espécies de carrapatos infectadas por R. bellii no continente americano

Borrelia infection in Ixodes pararicinus ticks (Acari: Ixodidae) from northwestern Argentina

The aim of this work was to describe for the first time the presence of Borrelia burgdorferi sensu lato infecting ticks in Argentina. Unfed specimens of Ixodes pararicinus collected from vegetation in Jujuy Province were tested for Borrelia infection by PCR targeting the gene flagellin (fla), the rrfA-rrlB intergenic spacer region (IGS) and the 16S rDNA (rrs) gene. One male and one female of I. pararicinus collected in Jujuy were found to be positive to Borrelia infection with the three molecular markers tested. Phylogenetically, the Borrelia found in I. pararicinus from Jujuy belongs to the B. burgdorferi s.l complex, and it was similar to one of the genospecies detected in I. aragaoi from Uruguay. Also, this genospecies is closely related to two genospecies known from USA, Borrelia americana and the Borrelia sp. genospecies 1. The epidemiological risk that implies the infection with Borrelia in I. paracinus ticks from Argentina appears to be low because the genospecies detected is not suspected of having clinical relevance and there are no records of Ixodes ticks biting humans in the southern cone of South America. Further studies are needed to assess accurately if there is risk of borreliosis transmitted by ticks in South America.EEA RafaelaFil: Nava, Santiago. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Barbieri, Amália Regina Mar. Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia. Departamento de Medicina Veterinária Preventiva e Saúde Animal; BrasilFil: Maya, Leticia. Universidad de la República. CENUR Litoral Norte. Centro Universitario de Salto. Laboratorio de Virología Molecular; UruguayFil: Colina, Rodney. Universidad de la República. CENUR Litoral Norte. Centro Universitario de Salto. Laboratorio de Virología Molecular; UruguayFil: Mangold, Atilio Jose. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Labruna, Marcelo B. Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia. Departamento de Medicina Veterinária Preventiva e Saúde Animal; BrasilFil: Venzal, José Manuel. Universidad de la República. Facultad de Veterinaria. Laboratorio de Vectores y Enfermedades Transmitidas; Urugua

Environmental infestation and rickettsial infection in ticks in an area endemic for Brazilian spotted fever

Brazilian spotted fever (BSF), caused by Rickettsia rickettsii, is endemic in the municipality of Americana, southeastern Brazil, where the disease is transmitted by the tickAmblyomma cajennense. This study evaluated the tick fauna and rickettsial infection in free-living ticks that were captured monthly using dry ice traps in areas endemic for BSF in Americana, from July 2009 to June 2010. Two tick species were captured: A. cajennense (6,122 larvae; 4,265 nymphs; 2,355 adults) and Amblyomma dubitatum(7,814 larvae; 3,364 nymphs; 1,193 adults). The immature stages of A. cajennense and A. dubitatum had similar distribution through the 12-month period, with larvae of both species collected in highest numbers between April and July, and nymphs between June and October. The highest numbers of A. cajennense adults were collected between October and December, whereas A. dubitatum adults were collected in relatively similar numbers throughout the 12-month period. Rickettsial infection was evaluated by means of PCR in 1,157 A. cajennense and 1,040 A. dubitatum ticks; only 41 (3.9%) A. dubitatum were found to be infected byRickettsia bellii. The present study showed that the areas of Americana that are endemic for BSF are characterized by high environmental burdens of A. cajennense and A. dubitatum