The incidence of canine filariosis in Central Europe in the past was rare and associated with import. Movement of dogs across countries has contributed to spreading of filariae to new areas. We investigated occurrence of dirofilariosis in the Czech and Slovak Republic. Finding of microfilariae in blood of two dogs from Slovakia on occasion of haematological testing in May 2005 became an impetus for taking and analysing blood samples of other dogs. In Czech Republic we started investigation in December 2005 and January 2006. Slovak group consisted of 21 dogs and Czech group of 30 dogs. Microfilariae were detected using the Knott test and determinated with the histochemical method based on the activity of acid phosphatase. For serological detection of D. immitis antigen we used the PetChek® kit. In Slovak group we found positive 12 out of 21 dogs. We identified microfilariae of D. repens in 12 dogs and D. immitis in two dogs simultaneously with D. repens. Serological testing detected D. immitis antigen in 3 dogs. In Czech group we found positive 7 out of 30 dogs. Microfilariae were detected by the Knott test in 4 dogs but only in 1blood smear where agreed with D. repens. Serological detection of D. immitis antigen was positive in 3 dogs. No microfilariae D. immitis were detected. The intensity of infection of dirofilariosis has been still lower than in Slovakia. Dogs were without specific clinical signs only 1 of them from the Slovak Republic and D. immitis positive manifested higher weariness.
Dirofilaria repens and Dirofilaria immitis have colonized the Czech and Slovak Republic.