Dirofilaria spp. Detection in Dog Blood Samples from Southern Poland—A Retrospective Data Analysis

Dirofilaria spp. is an etiological agent of dirofilariasis, a mosquito-borne parasitic disease of increasing zoonotic concern in Europe. The aim of this study was to assess the occurrence of Dirofilaria spp. in dogs from Southern Poland using retrospective data from a commercial veterinary diagnostic laboratory (Vetlab, Katowice, Poland). Blood tests from 2060 dogs were analyzed between 1 August 2018 and 31 December 2022. All samples were collected by the clinicians during routine veterinary activity and examined by a specific test—microscopic (blood smear/blood smear and Knott’s test), molecular or both—from the Vetlab laboratory offer (test selected by clinician). Out of all examined dogs, 19 (0.92%) tested positive for Dirofilaria. Positive samples originated from the Śląskie (n = 13), Opolskie (n = 3), and Małopolskie (n = 3) voivodeships. Co-infections with Babesia spp. and Anaplasma spp. were identified in two blood samples. This study demonstrates the presence of Dirofilaria spp. in dogs from Southern Poland, a region where data about dirofilariasis cases remain limited. Its overall occurrence was low in comparison to endemic areas in Central Poland. However, the presence of confirmed cases highlights the need for increased veterinary awareness, implementation of preventive measures, and further molecular epidemiological studies to better evaluate the risk of exposure to Dirofilaria in this region.