Infections with ehrlichia occur worldwide. Ehrlichia are gram-negative, obligate intracellular bacteria belonging to the order Rickettsiales and are transmitted by ticks. Depending on the region, the tick species differ and thus also the species of ehrlichia. Whereas in Mediterranean countries and tropical as well as warmer areas, Rhipicephalus sanguineus, the main carrier of E. canis, is prevalent, Ixodes ricinus is found in Central and Northern Europe. However, if R. sanguineus is introduced into Germany, it can survive in heated rooms. Infection with Ehrlichia canis still rather presents a “typical” travel-related disease or can mainly be found in imported animals.
An infection with E. canis leads to an infection of the monocytes and thus to canine monocytic ehrlichiosis (CME). The incubation period is about 8 – 20 days, which then changes into an acute phase of 2 – 4 weeks. Clinical signs are mostly non-specific: fever, anorexia, dyspnoea, anaemia, lymphadenopathy. In rare cases, CNS disorders may occur. In the first 10 – 20 days, thrombocytopenia can be seen, although there is rarely spontaneous bleeding. Subsequently, if untreated, a subclinical stage develops, which lasts for months or years, or chronic infections arise, which are often accompanied by hypergammaglobulinaemia. E. canis can also infect cats!