Equine parafilariosis in Iran.

From March to September 1991, horses (n = 1567), donkeys (n = 112) and mules (n = 96) were examined for equine parafilariosis by random sampling from different areas of Iran. The clinical signs of equine parafilariosis were observed in 136 cases of two northern areas (1.4% and 41.3% infection rate) and one northeastern area (6.3% infection rate). Most of the infected cases were confirmed by laboratory findings. All infected cases were followed up to establish the epidemiological features. The results suggest that there is one enzootic area in Iran, the Caspian coast and Persian Turkman steppes. An annual period of appearance of clinical signs coinciding with warm months was observed in all infected areas. No clinical sign was observed in cases less than 2 or more than 15 years of age. The highest infection rates (41.1-73.3%) were observed in equidae 4-9 years of age. The enzootic area encompasses the Caspian littoral, steppes and forest steppes and has an altitude of up to 1500 m. It has a temperature-wet climate. The treatment of 15 infected cases with ivermectin subcutaneously at 0.2 mg kg-1, was 100% effective with only one injection.