Prevalence of Dirofilaria immitis infection in dogs from Aydin and Izmir Provinces, Turkey

Mosquito-borne nematodes, Dirofilaria immitis and D. repens are among the most important filarial parasites of dogs. D. immitis is the causal agent of heartworm that primarily infects domestic and wild canids. Rarely, humans become accidental hosts to this parasite. D. repens, which is the main agent of human dirofilariosis, usually causes a non-pathogenic, subcutaneous infection in dogs. The aim of the present study was to investigate the prevalence of Dirofilaria spp. in the owned dogs in Aydin and Izmir regions using four different diagnostic techniques. To this end, blood samples were collected from 150 dogs in Aydin (n: 122) and Izmir (n: 28) provinces. The presence of the microfilariae of the parasite in the blood samples were examined by wet blood film method, modified Knott’s test, membrane filtration-acid phosphatase staining techniques and polymerase chain reaction (PCR). A commercial antigen test kit (HESKA Solo Step CH Batch Test Strips) was also used to detect adult D. immitis antigens in serum samples. The overall prevalence of D. immitis was % 10,0 as determined by both PCR and the antigen test kit. While the presence of the parasite determined by the modified Knott’s and membrane filtration tests was 4,67%, only four animals were determined to be positive by direct microscopic examination (2,67%). All positive samples were detected in Aydin, majority in the Germencik district. The prevalence of D. immitis was higher in male dogs (% 11,93) when compared to female dogs (%4,87). In conclusion, the present study demonstrates that canine dirofilariosis is prevalent in Aydın province (10,0%) of Turkey, even though the positivity is confined to a small area. Reliable epidemiological data is crucial to implement preventive control measures in order to decrease the incidence of canine dirofilariosis, which should be considered under the “One Health” concept in endemic areas.