Dirofilaria immitis conquering the regions in Slovakia previously endemic for D. repens

The present study was focused on the current state of Dirofilaria species distribution in the territory of the Slovak Danubian Lowland, a region previously identified endemic for Dirofilaria repens. For the research, blood samples of 330 dogs tested positive for dirofilariosis using concentration tests or "rapid heartworm tests" were sent by private veterinary practitioners for further DNA analyses and species determination. The results revealed an unquestionable change in the pattern of Dirofilaria species distribution with Dirofilaria immitis, diagnosed as the agent of mono- and co-infections with D. repens, responsible for 60.00% of all cases. The results showed that in the course of the last 5 years, D. immitis has spread significantly in Slovakia and has become the dominant causal agent of dirofilariosis in the former endemic areas of D. repens distribution, which increases infection risk for both dogs and humans.