Environmental Monitoring of Opportunistic Protozoa in Rivers and Lakes: Relevance to Public Health in the Neotropics

Water is a natural resource of vital importance to living beings, but due to anthropic action several microorganisms are disseminated into aquatic environments. In developing countries, over one billion people do not have access to clean, properly treated water and approximately three billion people do not have access to adequate sanitary facilities (Kraszewski et al., 2001) This scenery is probably a consequence of the increased environmental degradation, depletion of water resources, and constant contamination of bodies of water with wastewater and industrial effluents (Pedro & Germano, 2001), causing microorganisms from soil, faeces, decomposing organic matter, and other pollutant sources to spread into water. Goiania, the capital of the state of Goiás, located in the Midwestern Region of Brazil, has ca. 1.221.654 inhabitants and is considered a regional metropolis, among the major Brazilian cities that receive a large number of migrants (Alves & Chaveiro 2007). As a result, the city faces problems of disorderly and unsustainable urban growth with a consequent increase in superficial waste, which is a continuous source of contamination of water courses. The current sources of public water supply for the city of Goiania, the Meia Ponte river basin and its tributary river João Leite, are constantly submitted to degradation processes due to anthropic action, such as agriculture, intensive livestock production, and urbanization. And although all the water supplies of Goiânia come from this basin (52% from the Joa ̃o Leite River and 48% from the Meia Ponte River), this municipality is its largest polluter (Silva et al., 2010). Among the microorganisms that contaminate the aquatic environment, special attention should be given to opportunistic protozoa, such as Coccidea (Cryptosporidium parvum, Isospora belli, Sarcocystis sp., and Cyclospora sp.) and Microsporidia that infect the