Abstract
<jats:p>Dirofilariosis caused by Dirofilaria immitis represents an emerging vector-borne parasitic disease of major veterinary and zoonotic importance, requiring either simultaneous or sequential presence of definitive and intermediate hosts for transmission. Its distribution is closely linked to climatic conditions favorable for mosquito vectors, particularly in warm and humid regions. The present study aimed to assess the prevalence and epidemiological profile of D. immitis infection in dogs from Dolj County, southern Romania, an area characterized by a temperate-continental climate with high mosquito density. Between January 2024 and April 2025, blood samples from 260 dogs of various breeds, ages, and living conditions were collected and examined using three diagnostic methods: direct microscopic examination, the modified Knott’s test, and a rapid antigen test (Canine Heartworm Ag Senspert CHW). Microfilariae were detected in 11.5% of samples by microscopic examination, while the modified Knott’s test and rapid antigen test revealed prevalence rates of 15.4% and 16.5%, respectively. Dirofilaria repens was identified in 2.3% of dogs using the modified Knott method. Epidemiological analysis indicated a higher prevalence among dogs aged 2–6 years, predominantly in urban environments, with no significant sex-related differences. These findings confirm the circulation of D. immitis among the canine population in Dolj County and underline the value of complementary diagnostic approaches for accurate detection. The study contributes to updating the epidemiological map of dirofilariosis in Romania and highlights the need for continuous surveillance, preventive strategies, and increased public awareness to control this parasitic zoonosis.</jats:p>