Autochthonous cases of canine babesiosis in the canton Solothurn

Starting in November 2003 a series of five clinical cases of canine babesiosis was registered in the region of Obergosgen (canton Solothurn). All presented dogs showed increased body temperature, thrombocytopenia and hemoglobinuria, and none of the dogs had been abroad or visited endemic regions in the southern or western part of Switzerland so far. Babesia canis was detected in the blood smears of all five patients, but only three had detectable specific antibodies against this parasite. However, seroconversion was found in a second sample collected from the negative dogs at a later timepoint, confirming the diagnosis of canine babesiosis. The blood samples of two parasitized dogs were used for DNA-isolation and were tested with a Babesia-specific PCR, detecting the 18S rRNA-gene. Sequencing of the amplified products revealed a 100% identity with the sub-species B. caitis canis. The ticks Rhipicephalus sanguineus and Dermaccentor marginatus are potential vectors for B. canis. In the area where the infection with B. cauis was suspected a total of 152 ticks was collected and characterized; one was a female R. sanguineus. Although babesia could not be detected in the latter tick and the final proof for the complete life cycle is still lacking, it is very probable that B. canis has become autochthonous in the canton Solothurn.