Early manifestations of granulocytic ehrlichiosis in dogs inoculated experimentally with a Swedish Ehrlichia species isolate

Abstract

Seven beagles were inoculated experimentally with a Swedish canine Ehrlichia species isolate to study its pathogenicity. With respect to the 16S rRNA gene sequence, the isolate was identical to the human granulocytic ehrlichiosis (HGE) agent and closely related to both Ehrlichia equi and E phagocytophila. After an incubation period of four to 11 days, the most prominent clinical signs were high fever for two to five days and depression. All the dogs developed profound thrombocytopenia, moderate leukopenia and a strong serological antibody response. Ehrlichial inclusions were detected in blood neutrophils from four to 14 days after inoculation for four to eight days. Ehrlichial DNA could be detected by polymerase chain reaction during the parasitaemic stage and a few days before and after microscopic inclusions were visible. Postmortem, the dogs showed reactive splenic hyperplasia and non-specific mononuclear reactive hepatitis.

Genetic Variants of Anaplasma phagocytophilum Infecting Dogs in Western Washington State

“…Seven of the eight dogs had increased alkaline phosphatase values. These findings are very similar to those described for dogs in Minnesota, Wisconsin, and Sweden (11,17,18). None of the dogs had hypoproteinemia, hypoalbuminemia, hyperamylasemia, or regenerative left shift, as previously reported (11,18).…”

“…These findings are very similar to those described for dogs in Minnesota, Wisconsin, and Sweden (11,17,18). None of the dogs had hypoproteinemia, hypoalbuminemia, hyperamylasemia, or regenerative left shift, as previously reported (11,18). All but two of the dogs recovered rapidly, within 24 to 48 h after the initiation of treatment with doxycycline or tetracycline.…”

“…Age may be a susceptibility factor for A. phagocytophilum infection. Other authors have reported a similar age distribution, with all infected dogs being older than 1 year, whereas younger dogs had other tick-borne infections (11).…”

“…Five of the six dogs for which serological data were available were seropositive for A. phagocytophilum. Experimental studies with horses and dogs have documented that seroconversion to A. phagocytophilum occurs 2 to 5 days after the first appearance of morulae in the peripheral blood (11). The dog that tested negative for A. phagocytophilum by serology had appeared sick for 2 days, and an adequate acute-phase titer may not have been reached by that point.…”

Polymorphism and Transcription at the p44 - 1/p44 - 18 Genomic Locus in Anaplasma phagocytophilum Strains from Diverse Geographic Regions

“…A. phagocytophilum is transmitted to humans or animals by I. scapularis ticks in the northeast and upper midwest and by I. pacificus ticks in the western states (29,34,38). In Europe, I. ricinus is considered the main vector, but other ticks have also been implicated (27), and A. phagocytophilum occurs primarily in sheep and cattle and less frequently in humans than in the United States (2,7,10,13,15,(30)(31)(32)39 (25,27,33). Generally, human isolates can infect laboratory mice, but Massung et al (24) reported that strains isolated from wild deer cannot infect laboratory mice.…”