Prevalence of Dirofilaria repens in dogs from Lithuania

Abstract

Canine dirofilariasis cased by Dirofilaria repens and D. immitis during the past decade has become recognized worldwide as an emerging parasitic disease. The climate change, extensive movement of dogs across countries and continents has contributed to the expanding of distribution range of D. repens to the areas they had never been found before. In this study blood samples of 2180 randomly selected dogs presented in small animal clinic during 2014-2015 were investigated for filarial parasites. The microfilariae were determined on the basis of their morphometrical characteristics and the Diff-quick staining technique applied to blood smears and using Modified Knott’s test. For accurate identification of the filarial species we also used PCR with pan-filarial primers that amplify fragments of ITS-2 region of rDNA from six different filariae species and species specific primers for amplification of COI gene of D. repens. Microfilariae were detected in blood smears of 42 (1.9%) dogs. In four of dogs the adult worms were removed by using surgery technique. Adults worm were identified as D. repens based on the morphological and morphometric characteristics and PCR analysis. Sequence analysis confirmed D. repens in all PCR positive samples. Additionally, blood samples collected from 101 shelter dogs were investigated for filarial parasites using PCR. D. repens was detected in 18.9% (19/101) of tested dogs.