SEROPREVALENCE OF EHRLICHIA-CANIS AND OF CANINE GRANULOCYTIC EHRLICHIA INFECTION IN DOGS IN SWITZERLAND

Serum samples from 996 dogs in Switzerland were examined for antibodie s to Ehrlichia canis and to the agent causing canine granulocytic ehrl ichiosis (CGE), Ehrlichiosis, borreliosis, and systemic illness not as sociated with ticks were suspected in 75, 122, and 157 of these dogs, respectively. The remainder of the serum samples were obtained from cl inically healthy dogs which resided north (n = 235) or south (n 407) o f the Alps, The serum samples were tested by an indirect immunofluores cence technique for antibodies to the two agents incriminated, E. cani s and Ehrlichia phagocytophila, a surrogate marker of the agent of CGE , Twenty-two of 996 (2.2%) serum samples had antibodies to E, canis an d were distributed as follows: 20 of 75 (26.7%) samples from dogs susp ected of having ehrlichiosis, 1 of 122 (0.8%) from dogs suspected of h aving borreliosis, and 1 of 407 (0.2%) from healthy dogs which resided south of the Alps, Of the 75 (7.5%) serum samples that had antibodies to E, phagocytophila, significantly more samples were from ill dogs t han from healthy dogs. Among the sera from healthy dogs, antibodies to E, phagocytophila were significantly more prevalent In the north. Bec ause seropositive dogs had a history of travel outside Switzerland and because Rhipucephalus sanguineus is found exclusively south of the Al ps, it was presumed that, in contrast to the agent of CGE, E, canis is not indigenous to Switzerland.