feline dirofilariosis due to dirofilaria immitis in meshkin shahr district, northwestern iran

background: dirofilaria immitis is a common nematode of the cardiovascular system, which infects carnivores all over the world. the infection is prevalent in dogs, but in cats and human is rare. dirofilariosis is transmitted by mosquitoes. cats are accidental hosts and are naturally resistant to the infection, compared to the dogs. mild infection can cause severe illness in cats and may lead to death, so it is clinically important to diagnose the disease. methods: in the present study, 103 stray cats were collected from meshkin shahr district, aradabil province, northwestern iran that is an endemic area for canine dirofilariosis. blood samples were prepared from the saphenous vein of each cat and were examined for the presence of microfilariae by the modified knott test. results: a 2 yr old male cat (0.97%) was microfilaremic. the cat was subjected to necropsy and 4 adult d. immitis (2 male and 2 female worms) were found in the right ventricle of the heart. pcr was then carried out and d. immitis was confirmed. conclusion: cats and other carnivores in meshkin shahr district are at risk of infection due to the high activity of vectors in this climate and it is important to follow up the infection in this area.