GRANULOCYTIC EHRLICHIOSIS IN DOGS FROM NORTH-CAROLINA AND VIRGINIA

Medical records of 3 dogs from North Carolina and 3 dogs from Virginia with ehrlichial morulae in circulating neutrophils were studied retro spectively. Two clinically distinct disease syndromes, including chron ic, moderate to severe anemia (n = 3) and polyarthritis (n = 2) were a ssociated with canine granulocytic ehrlichiosis (CGE) in these dogs. O ne dog was clinically healthy, and abnormalities were not detected dur ing physical examination. Clinical signs were nonspecific and included fever, lethargy, anorexia, vomiting, and diarrhea. The most frequent laboratory abnormalities were normocytic normochromic nonregenerative anemia, moderate thrombocytopenia with large platelets, lymphopenia, a nd eosinopenia. Considerable variability was found in the serologic re sponses to Ehrlichia equi, Ehrlichia canis, and Ehrlichia chaffeensis antigens among the 5 dogs for which stored sera were available for ind irect fluorescent antibody testing. Polymerase chain reaction amplific ation and sequencing of portions of the 16S rRNA gene from blood (coll ected in ethylenediaminetetraacetic acid) of 1 severely anemic dog (do g 3) and 1 polyarthritic dog (dog 4) resulted in DNA sequences nearly identical to the GenBank accessions for Ehrlichia ewingii. The DNA seq uence from a 3rd doe (dog 5) was most similar to that of E. canis. Ser ologic or molecular results support the possibility of E. ewingii, E. equi, and E. canis coinfection or serologic cross-reactivity among can ine granulocytic and monocytic Ehrlichia species in dogs from North Ca rolina and Virginia. Variability in response to tetracycline or doxycy cline treatment was noted in these dogs, with more rapid resolution of signs in dogs with polyarthritis, We report the Ist cases of CGE in d ogs from North Carolina and Virginia, including recognition of CGE in a healthy dog.