This paper reports a spatial-temporal examination of waterborne disease data from the State of Mexico, 2000 to 2005, by county as the spatial unit. It was found that the incidence of waterborne disease did not decrease during the period under study. Inequality between metropolitan areas and rural zones was observed. People living in population centres had lower incidence of water-related diseases, possibly due to better access to services. In all cases, children under five years old suffered a much higher relative morbidity than the population in general. Improvement of the water distribution network between 2000 and 2005 could explain the decrease in morbidity from 30% to 15%, for the total population, and from 34% to 18.5%, for children under five years old. Coverage of sewer services over the period was not substantially improved; as a result the coefficient of determination remained nearly constant: 16.5% for the total population and 25% for children under five. Maintenance and operation deficiencies in the water distribution and wastewater sanitation systems play an important role in the incidence of this type of disease. It was found that the institutional division of the territory does not correspond to the actual distribution of the risk areas.
Keywords: developing countries, drinking water, GIS, Mexico, microbiological pollution, waterborne diseases