Prevention and control of diseases depend on how communities deal with human feces. At least 2.5 billion people in developing countries lack an adequate system for disposing of their feces. For the poor in many developing countries, feces deposited near their homes constantly threaten household hygiene, by direct contact with people or by being inadvertently carried into homes and kitchens by children, domestic animals or insects.
Domestic, neighbourhood or district water supplies such as well, tanks and reservoirs may be contaminated by poorly designed or maintained sewage disposal systems.
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The cleanliness of the water is not the only issue; the importance of an adequate water supply for household hygiene cannot be overemphasized. Washing hands after defecation and before preparing food is fundamental to controlling diseases, but even if this principle is understood fully, hand washing is impossible without sufficient water.
Improving the quality of drinking water, ensuring proper sewage disposal and providing more water for both personal and domestic hygiene are the keys to the prevention or control of major scourges such as diarrhoeal diseases (including cholera), typhoid, guinea-worm disease, schistosomiasis and giardiasis.
The estimates, relating to the developing world for 1995, indicate that about 25 per cent of the population do not have access to safe water and over 66 per cent lack adequate sanitation.
Technological advances in water supply, sanitation, drainage and solid wastes management in recent years offer cost-effective solutions that can be adapted to local circumstances and can greatly improve health and environmental conditions. Personal hygiene is immensely important in the prevention of contamination of food and drinking water.
The provision of a safe and adequate water supply requires partnership between communities and the organised public and private sectors, including NGOs. Government ministries concerned with education, development and industry have a major role to play. Communities can also take local initiatives for the provision of safe water, as demonstrated in Bolivia.
Deaths due to diarrhoeal diseases are particularly tragic because the great majority can be avoided by the prevention or treatment of dehydration, as the primary cause of death from acute diarrhoea is dehydration from the loss of fluids and electrolytes.
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Correct case management, both at home and in health facilities, can achieve immediate reduction in mortality from acute epidemic and non-epidemic diarrhoea in any age group.
This is achieved through the prevention of dehydration in the home by providing increased amounts of fluids and continuing to provide food or breast milk. Dehydration can be treated through the use of oral rehydration salts, and the use of intravenous fluids for severe dehydration. Antibiotics should be used only for dysentery and severe cases of cholera.
Outbreaks of giardiasis can also be prevented by adequate filtration and treatment of water supplies. The illness itself can be treated with drugs, but control measures have been hampered by lack of knowledge about the biology and natural history of the giardia organism. There is increasing evidence that its natural host is to be found among animals.
Cholera, which is definitely linked to poverty, is likely to occur when there is overcrowding coupled with lack of adequate sanitation and safe drinking water. Therefore the best long-term strategy to prevent cholera is elimination of the factors that favour its transmission, especially by improving water supplies and sanitation.
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The treatment of patients with rehydration therapy is the cornerstone of public health efforts to reduce cholera deaths. During acute emergencies, providing clean drinking water, basic sanitation and safe disposal of human waste are high-priority preventive interventions. Immunization is unlikely to be useful in epidemics.
Safe drinking water systems and adequate sewage disposal facilities are essential for the prevention of typhoid. Scrupulous cleanliness is necessary in food preparation and handling, as is proper storage of salads and other foods served cold.
A vaccine exists, but it does not give complete protection. Because of the increasing emergence of multi resistant bacterial strains, there is a greater need for longer-lasting, more effective vaccines. Research in this field is continuing.
The prevention and control of food-borne infections depend on improving the hygienic quality of raw foodstuffs at the agricultural level:
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Applying food processing technologies such as pasteurization, sterilisation, fermentation or irradiation; and, most critically, educating food-handlers in the principles of safe food preparation. Education of consumers and food-handlers is vital for the prevention of diarrhoeal diseases.
A vaccine for hepatitis A is available and is recommended for food-handlers. But because of its high cost, its uses has not been widely promoted. Here too, intersectoral cooperation is essential. Without it, health promotion and disease prevention cannot make headway. The responsibility for providing safe food should be shared between governments and the food industry, from producers to retailers.
Tetanus can never be eradicated because the spores which cause it will always remain in the environment to pose the risk of infection. But it can be eliminated as a public health problem—which means reducing its incidence to less than 1 case per 1,000 live births in each health district where it occurs.
This requires immunization of pregnant women and all women of childbearing age in high-risk areas. Hygienic childbirth practices are also a key element of prevention and are being promoted through a WHO “Clean Delivery” campaign.
Babies born to immunized mothers have a natural immunity to retain for up to 12 weeks. Women need two doses of vaccine to gain up to three years protection and five doses to cover all their childbearing years of maximum immune response.
The probable number of women living in high-risk areas who need three doses—which give five years’ protection—is 55 million. The estimated cost of immunizing them all is 84 million—equal to 1.53 per woman in 2000.
If world efforts to immunise infants with three doses of DPT are maintained, reinforcing infant immunization with a fourth dose of DPT at 15 to 24 months prolongs tetanus immunity for another five years. A fifth dose of tetanus toxoid (Given as Td of DT vaccine) at school entry will provide immunity for another 10 years. An additional doses when leaving school will ensure sufficient immunity for all childbearing age years.
In a perfect world there would be adequate sanitation for all and shoes for everybody. In the real world neither applies and controlling rather than eliminating soil-borne intestinal parasitic infections will remain the realistic goal until they do apply.
WHO promotes the regular use of single-dose, safe, cheap and effective drugs to combat the effects of intestinal worms infections. Research shows that in populations at risk, more of the worms are harboured by a small part of the population. This implies that it is most cost-effective to identify and treat the group that is most heavily infected.
In 2000, WHO studies in Zanzibar (United Republic of Tanzania) indicate that regular anthelminthic treatment with mebendazole (2.8 US cent a dose) significantly improves the iron status of school-children.
In areas where there is a high risk of hookworm infection and where many women have anaemia, WHO recommends that specific anti-hookworm chemotherapy should be included in strategies designed to improve the health, development and nutritional status of girls and women.