A MOLECULAR AND SEROLOGIC SURVEY OF EHRLICHIA-CANIS, E-CHAFFEENSIS, AND E-EWINGII IN DOGS AND TICKS FROM OKLAHOMA

Polymerase chain reaction and Southern hybridization were used to surv ey for the presence of Ehrlichia canis, Ehrlichia chaffeensis, and Ehr lichia ewingii in blood samples of 65 dogs that harbored ticks from no rthcentral and northeastern Oklahoma. Dog blood samples were also exam ined for antibodies against E. canis and E. chaffeensis, using an immu nofluorescent antibody test. Ten of 65 dogs (15.4%) examined were posi tive for Ehrlichia spp. by PCR. Four (6.2%) were positive for E, ewing ii, 2 (3.1%) for E, canis, and 4 (6.2%) for E. chaffeensis. Seven dogs (10.8%) were seropositive for E. canis or E. chaffeensis. Ticks colle cted from PCR-positive dogs were examined by PCR for the presence of E hrlichia DNA. Several groups of ticks were PCR-positive for E, ewingii or E, canis. E. canis was detected in Rhipicephalus sanguineus, which is considered the major vector for that organism. E. ewingii was dete cted in a larger variety of ticks, including the only known vector Amb lyomma americanum, as well as in Dermacentor variabilis and R. sanguin eus. Results suggest that Ehrlichia spp. which are canine and human pa thogens circulate in dogs in Oklahoma and in several tick species that feed on dogs. (C) 1998 Elsevier Science B.V. All rights reserved.