Water for people.pdf - WHO Thailand Digital Repository

1 0 2 / C H A L L E N G E S T O L I F E A N D W E L L - B E I N GBasic Needs and the Right to HealthThe Burden of Water-Associated Ill-HealthEvery day, diarrhoeal diseases cause an estimated 5,483 deaths, mostly among children under five. The World HealthOrganization (WHO) global estimate of the number of deaths from infectious diarrhoeas in the year 2001 amountsto 2 million for all age groups, with a heavy toll among children under five: an estimated 1.4 million deaths.Similar WHO estimates indicate that malaria kills over a millionpeople every year, and a large percentage of them are under five aswell, mainly in Africa south of the Sahara. Worldwide, over 2 billionpeople are infected with schistosomes and soil-transmittedhelminths and 300 million of these suffer serious illness as a result.In Bangladesh alone, some 35 million people are exposed, on a dailybasis, to elevated levels of arsenic in their drinking water, which willultimately threaten their health and shorten their life expectancy.These absolute numbers are dramatic in their own right. Theystand out against a much larger cluster of water-associated illhealth;for example, certain malignant tumours with a suspectedlink to long-term exposure to pollutants in water, for which thefractional attribution to specific determinants still needs to be firmlyestablished. The cluster of ill-health is even more insidious in itsimpact on the economics of countries and on livelihoods at thehousehold level. Water-associated diseases hit the poor in adisproportionate way and this burden of ill-health maintains thevicious cycle in which poverty leads to more ill-health, and more illhealthimplies further impoverishment.Water, sanitation and hygiene are three intertwined determinantsof the water/ill-health/poverty spectrum, with hygiene to beconsidered in its broadest sense, including environmental as well aspersonal hygiene. The associated burden of disease is not only felt inthe world today, it also affects the potential of future generations. Themost important category of personal hygiene-related diseases affectingschool-age children is intestinal helminth infections. These parasitesconsume nutrients, aggravate malnutrition, retard children’s physicaldevelopment and result in poor school attendance and performance.The outlook is bleak. Helminth infections destroy the well-being andlearning potential of millions of children. Each year 19.5 million peopleare infected with roundworm and whipworm alone, with the highestrate of infection among school-age children. Schistosomiasis (bilharzia)is also a young people’s disease; an estimated 118.9 million childrenunder fifteen years are infected.The full picture of water-associated ill-health is complex for anumber of reasons. As stated, the burden of several disease groupscan only partly be attributed to water determinants. This holds trueeven for diseases whose link to water at first sight may seemobvious and exclusive. Infectious diarrhoeas for example, are in partfood-borne. For the part that is water-borne, there may benumerous exposure routes, operating in combinations that are oftenlocation specific and may change over time. These multipletransmission pathways may be synergistically or antagonisticallylinked. Where water plays an essential role in the ecology ofdiseases, it may be hard to pinpoint the relative importance ofaquatic components of the local ecosystem. And, when it comes todisease prevention and control, there are methodological obstaclesto a cost-effectiveness analysis of health sector versus watermanagement interventions that will satisfy all parties concerned.The diseases and conditions of ill-health directly associated withwater, sanitation and hygiene include infectious diarrhoea (which, inturn, includes cholera [see box 5.1], salmonellosis, shigellosis,Box 5.1: Cholera in 2001Cholera, caused by a variety of strains of the bacterium Vibriocholerae, remains a global threat and a challenge to countrieswhere access to safe drinking water and basic sanitationcannot be ensured for all. In 2001, fifty-eight countries from allregions of the world officially reported to the WHO a total of184,311 cases and 27,728 deaths. Compared to the year 2000the case fatality rate (CFR) dropped from 3.6 to 1.48 percent.This drop can be attributed almost entirely to the extremely lowCFR of 0.22 percent in the cholera outbreak in South Africawhich accounted for 58 percent of the global total of reportedcases. Leaving aside the South African outbreak, the CFRdiminished only slightly to 3.21 percent from 3.9 percent in2000. With a total of 173,359 cases, Africa accounted for94 percent of the global total of cholera cases. Case numbersreported from Asia remained stable (around 10,000), while animportant decline was observed in the Americas.Despite efforts by many countries to contain the spreadof cholera, the disease is once more on the rise worldwide.Officially notified cases do not reflect the overall burden ofthe disease, because of underreporting, trade-relatedsanctions and other limitations in the surveillance andreporting system.Source: WHO, 2002c.