Dr. YANG Min’s research team from the State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences (RCEES), CAS, has made a series of important progresses in Cryptosporidium infection risks.

Cryptosporidium is considered to be one of the major health risks for gastroenteritis in the world. In the year 2000, there were 15 documented outbreaks of waterborne Cryptosporidium in the America alone. In some countries, cryptosporidiosis is listed as a notifiable disease. Thus, risk assessment of Cryptosporidium has been used as an important tool in many countries to help make environmental decisions to control its health effects. In China, Cryptosporidium has been detected in many provinces, with concentrations of 0–22 oocysts/10 L in source water, which is in accordance with those (0.67–13.4 oocysts/10 L) reported in other countries where outbreaks of cryptosporidiosis have occurred.

Dr. YANG Min’s research team investigated the occurrence of Cryptosporidium in source water of a city in Zhejiang river-network region in the rainy season of 2008. The research result suggests that for people who consumed conventionally treated water, the DALYs due to Cryptosporidium infection were 6.51 per 10⁵ persons (95% CI: 2.16×10^–5–22.35×10^–5), which were higher than acceptable risk level judged by some researchers (1.97×10^–5 DALYs per year), and the risk for those consuming ozone-treated water became 0.0689×10^–5 DALYs per year. The major risk of infection resulted from swimming in the river. This study provides a method to establish the risk assessment of Cryptosporidium infection and optimize the scheme for reducing the risk effectively, which is useful for the modification of water quality standards based on cost utility analysis given use of DALYs. The research was published in Environ Sci Technol. 2011, Jun 1; 45(11):4951-8.