1887

Abstract

A canine model for human monocytic ehrlichiosis was used to assess persistent infection and antigenic variation of . Two beagle dogs were infected subcutaneously with Arkansas strain. The dogs were observed for 6 months after inoculation for clinical signs, blood chemistry changes, antibodies to and presence of in the blood. Both dogs developed thrombocytopenia, but exhibited normal body temperatures during the entire course of infection. In one dog, was cultivated for up to 74 days post-inoculation and DNA was detected in the dog's blood for up to 81 days. In the other dog, was cultured for up to 102 days and DNA was detected in the blood for up to 117 days. PCR amplification and DNA sequence analysis indicated that there was no genetic variation in the 120 kDa outer-membrane glycoprotein gene of during infection of the dogs. The dogs developed antibodies to the immunodominant proteins of , including the 175, 140, 120, 80, 50 and 28 kDa proteins, starting in the fifth week post-inoculation. The dogs maintained high antibody titres throughout the 6-month study period. These results indicate that dogs become carriers of for 2–4 months after infection without exhibiting signs of clinical disease, suggesting that dogs may serve as a natural host for .

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2003-11-01
2019-11-12
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