The present status of human helminthic diseases in Iran

Over the last few decades there have been several marked changes in the human helminthiases found in Iran. Fascioliasis is emerging as an important chronic disease of humans, especially in the northern province of Gilan (where outbreaks in 1989 and 1999 involved >7000 and >10,000 cases, respectively) and, more recently, in the western province of Kermanshah. In contrast, no cases of urinary schistosomiasis, a disease that once affected thousands of individuals in south-western Khuzestan province, have been reported in Iran in recent years, and no cases of dracunculiasis have been seen in the country since the mid-1970s. Approximately 1% of all admissions to surgical wards are attributable to cystic echinococcosis, which is still considered endemic, but only a few cases of alveolar echinococcosis have been recorded. Over the last decade, there appears to have been a generally downward trend in the incidence of intestinal helminthiases in Iran. Recent estimates of the prevalences of ascariasis and strongyloidiasis, for example, lie between just 0.1% and 0.3%, and <1% of the population now appears to be infected with hookworm. In contrast, human infection with Hymenolepis and Enterobius remains relatively common. There have been a few case reports of toxocariasis and a few sero-epidemiological investigations of this disease but problems in accurate diagnosis have prevented good estimates of the general prevalence of this nematode infection. Just nine cases of pentastomiasis (all caused by Linguatula), 12 of dirofilariasis, one of gongylonemiasis, and three of moniliformiasis have been formally recorded in Iran.