isolation of acanthamoeba spp. from different environmental sources

background: acanthamoeba spp . are free-living amebas found in a wide variety of natural habitats. the high percentage of acanthamoeba in different environmental sources represents a sanitary risk for public health especially contact lens users and immunocompromised patients. the aim of this study was to determine the presence of acanthamoeba spp. in different environments such as water, soil, dust and ophthalmology wards. methods: from march to november 2007, 80 samples were collected from numerous localities in tehran city including university campus, laleh park and ophthalmology center. sample types were water, soil, dust, cow faeces and medical in­strument. each sample was filtered through nitrate membrane and cultured on 1% non-nutrient agar. these plates were fol­lowed up daily for 2 weeks. monitoring continued for two months on a weekly basis.   results: overall, 46.25% of samples contained acanthamoeba spp. all of the soil samples had shown positive culture in contrast to tap water. of 61 dust samples, 28 were positive. interestingly, we were able to isolate acanthamoeba in treat­ment unit of an ophthalmology center in tehran. it should be mentioned that two cow faeces showed positive culture as well. conclusion: the widespread distribution of acanthamoeba spp. across the environmental sources and increasing numbers of hiv + patients and contact lens wearers, as well as its ability as a pathogen carrier for humans, demands  more awareness and knowledge for public as a risk for human health.