Prevalence of Dirofilaria immitis and Dirofilaria repens in outdoor dogs in Tehran Province, Iran

Dirofilaria immitis and Dirofilaria repens are the most common species of filarial nematodes described in dogs, which are endemic in Iran. The diagnosis of canine dirofilariosis is usually based upon the microscopical detection and identification of circulating microfilariae together with ELISA detection of serum circulating heartworm antigens or antibodies. The identification of the parasite species using the traditional approaches sometimes can lead to misdiagnosis. As a zoonotic disease, it is important to know the prevalence of Dirofilaria in Tehran that is the most crowded province with many outdoor and stray dogs in suburb areas. In this paper, we used modified Knott’s test and a single-step multiplex PCR to detect and differentiate D. immitis and D. repens. Blood samples were collected from 311 outdoor dogs from March to August 2017. A total of 28.35% of dogs were positive by PCR in which 2.3% and 26% were D. immitis and D. repens, respectively. The highest incidence of infection was between 1 and 2.5 years old age. No sex predilection was observed. In the west of Tehran, prevalence of D. repens was statistically more than the other areas (p < 0.05). Our results showed the importance of detection and control of dirofilariasis in dog population as an important zoonotic disease.