Global access to clean water

In 2010 about 85% of the global population (6.74 billion people) had access to piped water supply through house connections or to an improved water source through other means than house, including standpipes, "water kiosks", protected springs and protected wells. However, about 14% (884 million people) did not have access to an improved water source and had to use unprotected wells or springs, canals, lakes or rivers for their water needs.[1] A clean water supply, especially so with regard to sewage, is the single most important determinant of public health. Destruction of water supply and/or sewage disposal infrastructure after major catastrophes (earthquakes, floods, war, etc.) poses the immediate threat of severe epidemics of waterborne diseases, several of which can be life-threatening. A standpipe is a freestanding pipe fitted with a tap which is installed outdoors to dispense water in areas which do not have a running water supply to the buildings. In the United Kingdom, an "Emergency Drought Order" permits a water company to shut off the primary water supply to homes, and to supply water instead from tanks or standpipes in the streets. This was done in some areas during the 1976 heat wave, for example. In some Middle Eastern, Caribbean and North African countries a standpipe is used as a communal water supply for neighbourhoods which lack individual housing water service. In areas such as Morocco, standpipes often yield unreliable service and lead to water scarcity for large numbers of people.[1] This outcome is not based upon the unreliability of the hardware, but on the underlying condition of the population exceeding the carrying capacity of the region with respect to water resources. Waterborne diseases are caused by pathogenic microorganisms that most commonly are transmitted in contaminated fresh water. Infection commonly results during bathing, washing, drinking, in the preparation of food, or the consumption of food thus infected. Various forms of waterborne diarrheal disease probably are the most prominent examples, and affect mainly chi

dren in developing countries; according to the World Health Organization, such disease account for an estimated 4.1% of the total DALY global burden of disease, and cause about 1.8 million human deaths annually. The World Health Organization estimates that 88% of that burden is attributable to unsafe water supply, sanitation and hygiene. The term "waterborne disease" is reserved largely for infections that predominantly are transmitted through contact with or consumption of infected water. Trivially, many infections might be transmitted by microbes or parasites that accidentally, possibly as a result of exceptional circumstances, had got into water, but the fact that there might be an occasional freak infection need not mean that it is useful to categorise the resulting disease as "waterborne". Nor is it common practice to refer diseases such as malaria as "waterborne" just because mosquitoes have aquatic phases in their life cycles, or because treating the water they inhabit happens to be an effective strategy in control of the mosquitoes that are the vectors. Microorganisms causing diseases that characteristically are waterborne, prominently include protozoa and bacteria, many of which are intestinal parasites, or invade the tissues or circulatory system through walls of the digestive tract. Various other waterborne diseases are caused by viruses. (In spite of philosophical difficulties associated with defining viruses as "organisms", it is practical and convenient to regard them as microorganisms in this connection.) Yet other important classes of water-borne diseases are caused by metazoan parasites. Typical examples include certain Nematoda, that is to say "roundworms". As an example of water-borne Nematode infections, one important waterborne nematodal disease is Dracunculiasis. It is acquired by swallowing water in which certain copepoda occur that act as vectors for the Nematoda. Anyone swallowing a copepod that happens to be infected with Nematode larvae in the genus Dracunculus, becomes liable to infection. The larvae cause guinea worm disease.