Effects of Nutrient and Pesticide Loading on Aquatic Ecosystems as Pertaining to the Emergence and Transmission of Human Disease: The Case of “Swimmers’ Itch”

EPA Grant Number: FP917102
Title: Effects of Nutrient and Pesticide Loading on Aquatic Ecosystems as Pertaining to the Emergence and Transmission of Human Disease: The Case of “Swimmers’ Itch”
Investigators: Mischler, John Anthony
Institution: University of Colorado at Boulder
EPA Project Officer: Lee, Sonja
Project Period: September 1, 2010 through August 31, 2013
Project Amount: $111,000
RFA: STAR Graduate Fellowships (2010) RFA Text |  Recipients Lists
Research Category: Academic Fellowships , Fellowship - Ecosystem Services: Aquatic Systems Ecology


I propose a novel and integrative approach to understanding and mitigating one major aspect of disease risk: the poorly understood, but potentially important, links between nutrient-driven eutrophication and pesticide loading, and an increased risk of several vector-borne diseases. Do increases in (1) nutrients and (2) endocrine disrupting pesticides (such as atrazine) supplied to aquatic ecosystems lead to an increase in the risk of humans contracting cercarial dermatitis?


My research project seeks to determine the effects of water quality on emerging and emergent infectious diseases. In particular, I will be studying the effects of pesticides (such as atrazine) and eutrophication (caused by nitrogen and phosphorus loading via fertilizers, sewage, etc.) on freshwater ecosystems. I will concentrate on disease caused by trematode parasites, which have a complicated life cycle. Trematode parasites require an aquatic snail as first intermediate host.


I will use a combined field (pond study) and experimental (mesocosm study) approach to explore both the severity and underlying mechanisms of this issue.

Expected Results:

It is expected that nutrient additions (nitrogen and phosphorus in the form of fertilizers, sewage effluent, etc.) boost both food quantity and food quality for aquatic snails (the intermediate hosts for cercarial dermatitis). As a result, these grazers will be more competent hosts and produce more parasite cercariae over a longer period of time than snails in non-eutrophic conditions. Endocrine disrupting pesticides are expected to inhibit the immune response of snails to parasite penetration, thus making infection more widespread in the snail population. Both increased nutrients and pesticide application should work synergistically to increase infection in the snail population, thus increasing the risk of infection for the human population.

Potential to Further Environmental/Human Health Protection:

Enhanced understanding of these interactions will enable more accurate forecasting and management in areas where cercarial dermatitis is emerging.

Supplemental Keywords:

nutrients, pesticide, disease, nitrogen, phosphorus,, Health, Scientific Discipline, Environmental Chemistry, Health Risk Assessment, Risk Assessments, Biochemistry, aquatic ecosystem, chemical exposure, nutrient loading, endocrine disrupting chemcials, human health risk, analysis of chemical exposure

Progress and Final Reports:

  • 2011
  • 2012
  • Final