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.
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.