As child care and food handling become more centralized, food-borne diseases that spread easily in communal settings can flourish unless a concerted effort is made to prevent them.
So it is not too surprising that shigellosis, a sometimes severe form of food poisoning associated with poor personal hygiene, is rising rapidly throughout the country, newly released federal statistics indicate.
Shigellosis, which afflicts mostly young children, is also common in women of childbearing age and poor people of all ages.
Laboratory-confirmed cases of the disease that were reported to the Centers for Disease Control in Atlanta nearly doubled from 1986 to 1988 -- from an incidence of 5.4 per 100,000 people to 10.1 per 100,000.
The number of reported cases in 1988 -- 22,796 -- was the highest since the centers began a national surveillance program for the illness in 1965. But many cases are not reported.
The centers, in the Aug. 3 issue of their bulletin, Morbidity and Mortality Weekly Report, noted that many of the recently reported community-wide outbreaks of shigellosis have been difficult to control because the disease spreads so readily from one young child to another in day care centers and schools, where hand-washing practices are usually lax.
The disease is most often transmitted from person to person when hands are not properly washed after using the toilet or when food is consumed that was contaminated by an infected person who failed to follow standard hand-washing rules.
Infectious organisms can live in a person's intestinal tract for months, long after symptoms have gone.
Laboratory studies suggest that once the shigella organism gets into food, it may survive for weeks, even at freezer temperatures. The bacteria (several species can infect people) can multiply easily in moist foods that are held at room temperature, which is especially troublesome if the foods are then consumed unheated.
The disease occurs most often in summertime, when salads and other cold or uncooked foods are frequent fare.
However, if contaminated foods are cooked or thoroughly heated before they are consumed, the bacteria are destroyed and the food can be eaten safely. The bacteria also do not survive well in acidic foods.
Foods most commonly associated with transmission of shigellosis include salads, like potato, tuna, shrimp, macaroni and chicken, and ingredients that have been cut, diced or chopped and mixed with other foods that are not subsequently heated.
The disorder, like most other types of food poisoning, causes gastrointestinal upset, especially diarrhea. The diarrhea is often watery and voluminous and tends to worsen as the disease progresses.
Bloody mucus may be present in the stool. Other common symptoms are abdominal pain, fever, headache and vomiting.