We are studying the survival properties of Cryptosporidium parvum oocysts, a waterborne pathogen that has been the focus of debate in the New York City watershed for more than 15 years. The city does not filter its water, and normal levels of chlorine do not affect C. parvum oocysts. Our work has shown that the current filtration-avoidance criteria and control methods used by the New York City Department of Environmental Protection can safely protect the citizens of the city from C. parvum outbreaks.

We were interested in the interdisciplinary opportunities provided by this project. Public-health microbiology, parasitology, and environmental microbiology all come into play.

We have studied the environmental conditions that affect permeability of C. parvum oocysts in laboratory and soil-field experiments. We have also studied the relationship between oocyst surface chemistry and transport of the oocysts, including the environmental factors that influence transport from farm to water supply.

The results of survival and fate studies directly influence decisions that affect the public health of the citizens of New York City. The project has served as a model for the development of filtration-avoidance criteria and water safety rules promulgated by the EPA.

Departmental Chairman`s Add-on