I am trying to find data on how water quality (such as the presence of nitrates and phosphorus) correlates to infectious disease.
I have found many papers that discuss the approach and results, but have not been able to find any downloadable data that I can use to train a neural network, which will predict outcomes based on a given set of water quality data.
I work at Quandl and we have some databases that cover water quality and infectious diseases. Within each database, you can search for "water" or "infectious disease" to narrow the datasets presented to you.
Here are some databases showing datasets for "infectious disease":
Organisation for Economic Co-Operation and Development https://www.quandl.com/data/OECD-Organisation-for-Economic-Co-operation-and-Development?keyword=infectious%20disease
National Bureau of Statistics of China https://www.quandl.com/data/NBSC-National-Bureau-of-Statistics-of-China?keyword=infectious%20disease
National Institute of Statistics and Economic Studies (France) https://www.quandl.com/data/INSEE-National-Institute-of-Statistics-and-Economic-Studies-France?keyword=infectious%20disease
Here are some databases showing datasets for "water quality" - you may also want to try searching just "water" or "water sanitization":
WHO UNICEF https://www.quandl.com/data/WHO_UNICEF-Who-Unicef-Joint-Monitoring-Program?keyword=water%20quality
World Bank Africa Development Indicators https://www.quandl.com/data/WADI-World-Bank-Africa-Development-Indicators?keyword=water
UN Environment Statistics https://www.quandl.com/data/UENV-United-Nations-Environment-Statistics?keyword=water
UN Global Indicators https://www.quandl.com/data/UGID-United-Nations-Global-Indicators?keyword=water%20
Hope this helps somehow...
Surveillance for Waterborne-Disease Outbreaks --- United States, 1999--2000
EPA Technical Resources About Beaches - Including Data and Reports About Beach Health, Beach Advisory and Water Quality Data
EPA's HealthyWater - Information About Recreational and Drinking Water Outbreaks (and more)
Digging down into state/local levels takes time, but should provide more of what you are seeking; for example, VDH (Virginia Department of Health) has a lot resources/data for beach advisories, water quality, outbreak and infectious disease data.
Here are some water quality datasets for a project called Mackenzie Datastream.
This is limited to the Mackenzie river (Canada).
