Serologic and molecular evidence of Ehrlichia spp. in coyotes in California

In order to determine the role of coyotes in the epidemiology of granulocyt ic and monocytic ehrlichial agents in California (USA), we tested 149 serum samples for antibodies against Ehrlichia equi E. risticii, and E. canis, u sing an indirect immunofluorescent antibody test. Polymerase chain reaction (PCR) assay was used to survey for the presence of members of the E. phago cytophila genogroup, E. risticii and E. canis in blood samples of 95 coyote s. Sixty-eight (46%) samples were seropositive for E, equi, two (1%) for E. risticii and none of the samples had antibodies reactive to E. canis. Two and one coyote were positive for E. risticii and members of the E. phagocyt ophila genogroup by PCR assay, respectively. In contrast, the 95 samples we re negative for E. canis by PCR. Ninety-five percent of the 68 E. equi sero positive coyotes and the one coyote PCR positive for members of the E. phag ocytophila genogroup originated from a coastal area. However, the two E. ri sticii seropositive coyotes and the two coyotes PCR positive for E. ristici i were from northern California. Sequence analysis of the three amplified P CR products revealed the agent to be similar in two coyotes to the sequence s of E. risticii from horses originating from northern California and ident ical in one coyote to the agent of human granulocytic ehrlichiosis and E. e qui from California. Thus, coyotes are er;posed to granulocytic ehrlichiae and E. risticii and may play a role in the epidemiology of these ehrlichial agents in California.