# Case Study 1: Safe Drinking Water

This page is intended as a structural template for editors to use in adding their own case studies to the wiki.

This section describes the scenario you are going to be modeling. This could in paragraph format describing a real world question health professionals or policy makers may need to know.

This section is where you can research the pathogens you may be encountering in this scenario. In some cases you may know ahead of time which specific pathogen you are modeling. In other cases it will be more variable based on the particular environment. You may even be dealing with multiple organisms. Once the organisms are known, research them to determine transmission routes, case-fatality ratios, epidemiological histories, etc. More information on this section is available at the hazard identification home page.

In this section, you explore every pathway the pathogen can take from source to host. It can take considerable time, research and creativity to accurately model all the relevant parts. More information on this section is available at the exposure assessment home page.

This is the more mathematically intensive of the sections. Here you establish the type of model you will apply once you finish the exposure and hazard id. There are two basic equations you could use and countless possibilities for the variables. More explanation and a compilation of dose-response models is available at the dose-response home page

Once the exposures are understood and the dose-response relationship is known you can then put these parts together to provide a probability of infection based on a single time period or incidence. For more information and additional examples, visit the risk characterization home page.

Now that you know the nature of the risk, you can start to explore the various methods of reducing that risk. While this appears to be a more traditional form of environmental health, pairing it with the risk assessment framework you will know have an well developed idea of what parts of the infection chain would be most appropriate to target. This would be either because a certain part contributes a considerable amount of risk or because it is easily addressed. Also part of risk management is mathematica cost and effectiveness models that guide you as to how to carry out these management strategies. More information available at the risk management home page

### References

Espinosa, et al. Comparative study of enteric viruses, coliphages and indicator bacteria for evaluating water quality in a tropical high-altitude system. Environmental Health. 2009; 8:49.

Zambrano, et al. Spatial heterogeneity of water quality in a highly degraded tropical freshwater ecosystem. Environmental Management. 2009; 43:249–263.

Mazari-Hiriart, et al. Longitudinal study of microbial diversity and seasonality in the Mexico City metropolitan area water supply system. Applied and Environmental Microbiology. 2005; 79(9):5129-5137.

Espinosa, et al. Infectivity and genome persistence of rotavirus and astrovirus in groundwater and surface water. Water Research. 2008; 42:2618-2628.

Chavez, et al. The removal of microorganisms and organic micropollutants from wastewater during infiltration to aquifers after irrigation of farmland in the Tula Valley, Mexico. Environmental Pollution. 2011; 159:1354-1362.