Ehrlichia ruminantium (ER), the causative agent of heartwater on ruminants, is an obligate intracellular bacterium transmitted by ticks of the genus Amblyomma. Previous studies have shown that early stages of development may be critical for Ehrlichia pathogenicity. To gain insights into the biology of intracellular ER, we determined the genome-wide transcriptional profile of ER replicating insi...

BACKGROUND A novel Ehrlichia, closely related to Ehrlichia ruminantium, was recently discovered from Panola Mountain State Park, GA, USA. We conducted a study to determine if this agent was recently introduced into the United States. METHODS We developed a sensitive PCR assay based on the conserved gltA (citrate synthase) gene and tested DNA samples extracted from 1964 field-collected and 183...

Canine monocytic ehrlichiosis, caused by Ehrlichia canis or Ehrlichia chaffeensis, can result in clinical disease in naturally infected animals. Coinfections with these agents may be common in certain areas of endemicity. Currently, a species-specific method for serological diagnosis of monocytic ehrlichiosis is not available. Previously, we developed two indirect enzyme-linked immunosorbent as...

Ehrlichiosis is the multiorgan infectious disease caused by small, intracellular rickettsias from the genus Ehrlichia. These microorganisms are known as an etiologic factor of infections world wide in humans and in different species of animals. Dog ehrlichiosis can be caused by several species of Ehrlichia attacking different groups of blood cells, but most often an infection by Ehrlichia canis...

Serological surveys have confirmed Anaplasma marginale and Anaplasma phagocytophilum infections in dromedary camels, but molecular surveys and genetic characterisation of camel-associated Anaplasma species are lacking. In this study, we detected tick-borne Anaplasmataceae in 30 of 100 (30%) healthy dromedary camels screened using a combined 16S rRNA-groEL PCR-sequencing approach. Nucleotide seq...

The major outer membrane proteins (OMPs) of the human granulocytic ehrlichiosis (HGE) agent, with molecular sizes of 44 to 47 kDa, are immunodominant antigens in human infection. Monoclonal antibodies (MAbs) to the OMPs were made by immunizing BALB/c mice with the purified HGE agent and then by fusing spleen cells with myeloma cells. The immunologic specificities of three MAbs (3E65, 5C11, and ...

Pathogens transmitted by ticks are an emerging problem worldwide, this study aimed to diagnose the causal agents of infection in dogs presenting suspected hemoparasitoses. Fifty-eight dogs with clinical signs such as depression, hemorrhagic diathesis and fever were evaluated regarding clinical presentation, hemogram, blood smears and serological tests, using the indirect immunofluorescence meth...

Rickettsial pathogens in the genera Anaplasma and Ehrlichia cause acute infection in immunologically naive hosts and are major causes of tick-borne disease in animals and humans. Immunization with purified outer membranes induces protection against acute Anaplasma marginale infection and disease, and a proteomic and genomic approach recently identified 21 proteins within the outer membrane immu...

Serum samples of 749 sheep from 75 sheep flocks in Norway, i.e. 361 lambs (6 to 7 months old) and 388 adults (> 1.5 year), were analysed for antibodies to Ehrlichia equi. Ten animals from each flock were examined. Seropositive animals were found along the coast of southern Norway from Vestfold to Sør-Trøndelag (as far north as 63 degrees 38'N). Seropositive sheep were not found in southeast, ea...

The aims of this study were to determine the seroprevalence of Ehrlichia spp. and risk factors for exposure in a restricted population of dogs, horses, and humans highly exposed to tick bites in a Brazilian rural settlement using a commercial ELISA rapid test and two indirect immunofluorescent assays (IFA) with E. canis and E. chaffeensis crude antigens. Serum samples from 132 dogs, 16 horses a...