Infectious diarrhoeas

Generalized diarrhoea (particularly infectious forms) is the chief symptom of several serious diseases and is a major cause of death in the world. The frequent watery stools drain the body of its essential water and salts, and if this condition is not corrected, the diarrhoea sufferer may die. Infections of the bowel (viruses, bacteria, or parasites: E. coli, Salmonella, cholera, and parasites) are the main cause, and this is the consequence of poor sanitation and bad hygiene - both environmental and personal hygiene. Other infections also produce diarrhoea: typhoid fever, toxoplasmosis and hepatitis are examples.

Diarrhoeal infections also cause millions of lost working days each year, as well as much discomfort. One well documented source of infection is the consumption of shellfish (polluted by sewage) - and therefore, they also have economic consequences for fishermen and the food industry. Such viruses often cause mini-epidemics in families, hospital wards, etc and are potentially very dangerous to seriously ill hospital patients. More importantly, these viruses contribute to the massive mortality caused by infantile diarrhoea in developing countries and are responsible for uncounted millions of deaths each year.

In the many communities which have inadequate housing, and poor water supplies, cooking facilities and sanitation systems, it is difficult to prevent these infections. The condition is usually contracted by swallowing minute amounts of excreta from people who have infectious diarrhoea. Although an average adult takes in about 2 litres of fluid per day by mouth, and excretes about one tenth of that (0.2 litres) in the stools, large amounts of digestive juices are poured into the tubular tract, so that about 9 litres of fluid enter the system and are absorbed again every 24 hours. The germs causing diarrhoea usually stimulate excessive secretion into the bowel, but the ability of the gut to absorb is often not increased. The serious consequences of diarrhoea are thus the loss of essential water and salts in the liquid stools, in other words dehydration and electrolyte loss. A vicious cycle sets in: food-borne diseases lead to impaired digestion and malabsorption of nutrients, until resistance to illness is reduced, causing further illness. In many cases death occurs.

Diarrhoea continues to be a major cause of morbidity and mortality worldwide resulting in an estimated 1,000 deaths among children each day, the highest incidence being in developing countries of the world. Diarrhoeal diseases are most widespread in the developing countries; they are transmitted by human faecal contamination of soil, food and water, and direct infection usually occurs with contaminated food or drinking water. Nutritionally inadequate diets render the problem even more severe. As much as 70% of diarrhoeal diseases in the developing countries are now believed to be of foodborne origin. Repeated diarrhoea attacks are themselves one of the main causes of malnutrition. Only about a third of the people in the world's least developed countries have dependable access to a safe water supply and adequate sanitary facilities. Although there is a lack of reliable information, it has been estimated that in 1975 there were about 500 million cases of enteric infection (diarrhoea) in children under 5 years of age in Asia, Africa and Latin America.

Traveller's diarrhoea is the term used to describe the diarrhoea that strikes international travellers from countries with good hygiene to countries that have poor public sanitation and hygiene. It is caused by infection with one of a number of bacteria, protozoa or viruses that are ingested by eating food or drinking water that has been contaminated by stool. Of some 400 million people who travel each year for business, pleasure or other reasons, WHO estimates that 20 to 50% suffer from diarrhoea. In the majority of these cases this is caused by microbiologically contaminated foods or drinking water to which resistance is probably decreased by the stress of travel.

The VRE enterococcus strain is resistant to almost all known antibiotics.