RESUMO
The aim of this work was to describe two novel strains of Ehrlichia associated to Amblyomma tigrinum from Argentina. Molecular detection of agents belonging to the family Anaplasmataceae was performed targeting three different loci: 16S rRNA gene, dsb gene and a fragment of groESL heat shock operon. The results have shown that two different strains of Ehrlichia sp. associated to A. tigrinum are circulating in peri-urban areas of Argentina. The Ehrlichia strain detected in ticks from San Luis Province, named as Ehrlichia sp. strain San Luis, is closely related to the Ehrlichia chaffeensis. The novel Ehrlichia strain detected in Córdoba Province, named as Ehrlichia sp. strain Córdoba, is phylogenetically related to three Ehrlichia strains from Brazil, two of them isolated from wild carnivorous and the third one isolated from horse. Even though Ehrlichia sp. strain Córdoba was clustered with the three Ehrlichia strains from Brazil, the genetic similarity was too low to consider them as the same taxonomic entity. Blood samples of dogs were positive to Anaplasma platys. The association of these two novel strains with A. tigrinum has epidemiological relevance because adult stages of this tick species are common parasite of dogs in rural and peri-urban areas and they are aggressive to humans. The presence of these two novel Ehrlichia strains implies a potential epidemiological risk in Argentina because the species of the genus Ehrlichia are known to be pathogenic to both domestic mammals and humans.
Assuntos
Doenças do Cão/parasitologia , Ehrlichia/classificação , Ehrlichia/isolamento & purificação , Ixodidae/microbiologia , Infestações por Carrapato/veterinária , Animais , Argentina/epidemiologia , Brasil/epidemiologia , DNA Bacteriano , Doenças do Cão/epidemiologia , Cães/microbiologia , Cães/parasitologia , Ehrlichia/genética , Ehrlichia/patogenicidade , Ehrlichia chaffeensis/classificação , Ehrlichia chaffeensis/genética , Ehrlichia chaffeensis/isolamento & purificação , Humanos , RNA Ribossômico 16S , Infestações por Carrapato/parasitologia , População UrbanaRESUMO
Human monocytic ehrlichiosis is a febrile illness caused by Ehrlichia chaffeensis, an intracellular bacterium transmitted by ticks. In Mexico, a case of E. chaffeensis infection in an immunocompetent 31-year-old woman without recognized tick bite was fatal. This diagnosis should be considered for patients with fever, leukopenia, thrombocytopenia, and elevated liver enzyme levels.
Assuntos
Ehrlichiose/diagnóstico , Ehrlichiose/microbiologia , Adulto , Antibacterianos/uso terapêutico , Biópsia , Ehrlichia chaffeensis/classificação , Ehrlichia chaffeensis/genética , Ehrlichiose/tratamento farmacológico , Evolução Fatal , Feminino , Humanos , Fígado/microbiologia , Fígado/patologia , Testes de Função Hepática , MéxicoRESUMO
BACKGROUND: Diagnosis of canine ehrlichiosis in Venezuela is normally performed by examination of buffy coat smears (BCS). Characteristic inclusion bodies are frequently observed in leukocytes and platelets from dogs with clinical signs of the disease. OBJECTIVE: The purpose of this study was to investigate the co-infection of a dog with Ehrlichia canis and E hrlichia chaffeensis using microbiological and molecular techniques. METHODS: Primary cultures of monocytes from a dog showing signs of ehrlichiosis were performed. Ehrlichial inclusions in blood cells were demonstrated by BCS and in cultured cell smears with direct immunofluorescence and Dip Quick staining. Nested PCR analysis was performed with DNA from blood samples and cultures, using primers specific for E. canis and E. chaffeensis. The amplified DNA fragments were sequenced to confirm the specificity of the amplifications. RESULTS: The BCS of the naturally infected dog contained intracellular morulae. Ehrlichial inclusions were observed 9 days after inoculation of the primary cultures. After 3 passages with monocytes from a healthy dog, 65% of infected cells, and cells with >60 morulae were observed. A healthy female German Shepherd dog, seronegative for E. canis and E. chaffeensis antigens and without contact to ticks, was inoculated with an infected culture. The animal developed signs of canine monocytic ehrlichiosis and became seropositive. Nested PCR results and sequencing of amplified DNA fragments demonstrated the simultaneous presence of E. canis and E. chaffeensis in both dogs. CONCLUSIONS: This is the first report of E. chaffeensis in dogs in South America. This organism was previously identified in dogs by PCR only in the United States.