Three isolates of Ehrlichia ruminantium (Kümm 2, Omatjenne and Riverside), the causative agent of heartwater in domestic ruminants, were isolated in Ixodes scapularis (IDE8) tick cell cultures using the leukocyte fraction of infected sheep blood. All stocks were successfully propagated in IDE8 cells, whereas initiation attempts using endothelial cell cultures were unsuccessful. Therefore, the new technique should be included in any attempt to isolate field strains of E. ruminantium to enhance the probability of getting E. ruminantium isolates which might not be initiated in endothelial cells. Draft genome sequences of all three isolates were generated and compared with published genomes. The data confirmed previous phylogenetic studies that these three isolates are genetically very close to each other, but distinct from previously characterised E. ruminantium isolates. Genome comparisons indicated that the gene content and genomic synteny were highly conserved, with the exception of the membrane protein families. These findings expand our understanding of the genetic diversity of E. ruminantium and confirm the distinct phenotypic and genetic characteristics shared by these three isolates.
ABSTRACT: Anaplasma phagocytophilum is responsible for granulocytic anaplasmosis in humans and various animal species. The aim of the present study was to determine the prevalence of A. phagocytophilum-infected dogs in a residential area of Belo Horizonte, Minas Gerais state, Brazil. A total of 62 dogs were submitted to serological (indirect fluorescent-antibody -IFI) and molecular (PCR) tests. Anti-A. phagocytophilum antibodies were detected in 43.8% of the dogs. Seven dogs (10.9%) were PCR-positive for the msp4 gene, six and four of these were positive for the for the msp2/p44 gene of A. phagocytophilum and 16S rRNA region of granulocytic Anaplasmataceae respectively. This study confirms a relatively high frequency of A. phagocytophilum infection in a population of domiciled dogs in an urbanized area in south-eastern Brazil and highlights the need for further studies on the role of Rhipicephalus sanguineus sensu lato ticks in the transmission of this bacterium to dogs in urban Brazilian areas.
RESUMO: Anaplasma phagocytophilum é responsável pela anaplasmose granulocítica, doença que acomete seres-humanos e várias espécies de animais. O objetivo do presente estudo foi determinar a prevalência de cães acometidos por A. phagocytophlium em uma área residencial de Belo Horizonte, MG, Brasil. Sessenta e dois cães foram submetidos a testes sorológicos (reação de imunofluorescência indireta - IFAT) e moleculares (PCR). Anticorpos anti-A. phagocytophilum foram detectados em 43,8% dos cães. Sete cães (10,9%) foram positivos no PCR para o gene msp4 de A. phagocytophilum, seis para o gene msp2/p44 A. phagocytophilum e quatro para a região 16S rRNA de Anaplasmataceae granulocíticas. Esse estudo confirma a frequência relativamente alta da infecção por A. phagocytophilum em uma população de cães domiciliados em área urbanizada no sudeste do Brasil e destaca a necessidade de pesquisas para determinar o papel do carrapato Rhipicephalus sanguineus sensu lato na transmissão desse microrganismo para cães de áreas urbanas brasileiras.