Background and purpose: Dirofilaria immitis is one of the most important pathogenic Nematoda for humans and carnivores, especially dogs. It causes a zoonotic disease, namely dirofilariasis in hosts with a wide variety of manifestations. The detection of infection is commonly carried out by different microscopic and serologic methods and recently by molecular techniques. This aim of this research was to provide an accurate assessment of the D. immitis infection rates in dogs in Tabriz and its suburbs using molecular technique and determination of the influence of epidemiological factors on infection rates.

Materials and methods: A descriptive study was performed in which a total of 121 dogs including sheepdogs, house dogs, guard dogs, commercial dogs and stray dogs (aged <2, 2-4 and 4< years old) were randomly selected from different areas in Tabriz, Iran. Blood samples were taken from the cephalic vein. To detect and assess the infection rates, after DNA extraction, a fragment of 432bp related to 18srRNA region was selected and amplified using specific primers.

Results: Fourteen blood samples (11.6%, mainly of sheepdogs) were found to be positive for
D. immitis. The prevalence rates of infection showed significant differences between geographical
areas (P= 0.36).

Conclusion: Despite great progress in prevention and control of parasitic diseases, dirofilariasis still occurs in canine community in East Azarbaijan province. Dog owners and veterinary services are recommended to pay ample attention to protect dogs against D. immitis infection and prevent subsequent transmission of infection to humans.