Investigating Acanthamoeba in Coastal Waters of Caspian Sea in Guilan Province, Iran

Background: Acanthamoeba spp., can cause severe and fatal diseases including encephalitis, skin granulomatous and keratitis. Contaminated waters can be a threat to high risk people such as contact lens wearers, patients with eye surgery or eye trauma, and immunocompromised patients.  Objective: The present study aims to investigate the presence of potentially pathogenic Acanthamoeba in coastal water of Caspian Sea in Guilan Province, Iran based on morphological criteria and thermotolerance assay. Materials and Methods: In this descriptive study conducted in 2018, a total of 60 water samples were collected randomly from the shores of Rudsar, Chamkhaleh, Kiyashahr, Zibakenar and Bandar-e Anzali (12 samples of 500 mL from each site). Water was filtered by cellulose nitrate membranes with a 0.45 µm pore size and then cultured on non-nutrient agar. They were checked daily for the presence of Free-Living Amoeba (FLA) based on morphologic characteristics of both trophozoite and cyst using a light microscope (100X). Thermotolerance assay was used to determine the potential pathogenicity of Acanthamoeba spp., and its growth was examined at a temperature of 42°C. Results: FLA were grown in 30 out of 60 samples (50%) at a room temperature and in 8 (26.6 %) at a temperature of 42°C. Acanthamoeba were identified in all sampling sites, where 8 samples were potentially pathogenic using thermotolerance assay. Conclusion: There is pathogenic Acanthamoeba spp in coastal waters of Caspian Sea in Guilan Province. Since this province attracts many tourists annually, it is necessary that high-risk people including contact lens wearers and immunocompromised patients in this area be warned by health organizations.