RESEARCH ARTICLE Contribution of environmental media to cryptosporidiosis and giardiasis prevalence in Tehran: a focus on surface waters Mahdi Hadi 1 & Alireza Mesdaghinia 1,2 & Masud Yunesian 2,3 & Simin Nasseri 1,2 & Ramin Nabizadeh Nodehi 2,3 & Hamidreza Tashauoei 4 & Esfandiar Jalilzadeh 5 & Roya Zarinnejad 5 Received: 29 December 2015 /Accepted: 7 June 2016 # Springer-Verlag Berlin Heidelberg 2016 Abstract The occurrences of Cryptosporidium and Giardia in surface sources of drinking water in Tehran were moni- tored, using US EPA method 1623.1. The prevalence ratios (PR) of positive samples among other media (animal’ s stools, vegetables, and human’ s stools) were also estimated from lit- erature data. The density of Giardia and Cryptosporidium in water samples were 0.129 ± 0.069 cysts/L and 0.005 ± 0.002 oocysts/L, respectively. Estimated PR in vegetables, animal stools, surface waters, and human stools were 6.65, 20.42, 21.05, and 4.28 % for Cryptosporidium and 6.46, 17.13, 73.68, and 15.65 % for Giardia, respectively. These reveal the importance of surface waters’ and animal stools’ roles in the prevalence of cryptosporidiosis and giardiasis in Tehran’ s population. Giardia’ s prevalence in untreated surface waters in Tehran was found 3.5 times as much as Cryptosporidium while this found 2.3 times on a global scale. Moreover, the prevalence of giardiasis to cryptosporidiosis infections in Tehran’ s human population was 3.65. These values could be a clue to attribute the infections to the occurrence of parasites in surface waters. Significant (p < 0.05) associations were observed between rainfalls and presence of Giardia (r = 0.62) and Cryptosporidium (r = 0.60) in surface waters. In autumn, rainfalls can increase the parasites occurrences in surface wa- ters. Significant (p < 0.05) difference on the density of para- sites was found between some seasons using Kruskal-Wallis and multiple comparison tests. A significant correlation (r = 0.86) between Giardia and Cryptosporidium densities also confirms the common sources of pollution in surface waters. Findings suggest that untreated surface waters in Tehran may be a potential route of human exposure to proto- zoan parasites. Keywords Cryptosporidium . Giardia . Surface water . Protozoan parasites . Parasites occurrence Introduction Cryptosporidium spp. and Giardia spp. are two main proto- zoan pathogens having worldwide distribution. They both have numerous species and subtypes identifiable by molecular means (Bakheit et al. 2008; Monis and Thompson 2003; Xiao and Fayer 2008). Many of them have been recognized as infectious agents to the human population (Fayer et al. 2006; Robinson et al. 2008). Today, several Cryptosporidium spe- cies including two species in fish, 1 in amphibians, 2 in rep- tiles, 3 in birds, and 12 in mammals have been recognized and based on SSUrRNA sequence nearly 61 Cryptosporidium ge- notypes with uncertain species status have been found (Plutzer Communicated by: Philippe Garrigues * Alireza Mesdaghinia mesdaghinia@sina.tums.ac.ir 1 Center for Water Quality Research (CWQR), Institute for Environmental Research (IER), Tehran University of Medical Sciences, Tehran, Iran 2 Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran 3 Center for Air Pollution Research (CAPR), Institute for Environmental Research (IER), Tehran University of Medical Sciences, Tehran, Iran 4 Department of Environmental Health Engineering, School of Public Health, Islamic Azad University-Tehran Medical Branch, Tehran, Iran 5 Department of Water and Wastewater Quality Control Laboratory, Water and Wastewater Company, Tehran, Iran Environ Sci Pollut Res DOI 10.1007/s11356-016-7055-9