ATLANTA (AP) - Thousands of children are being exposed to dangerous E. coli bacteria at petting zoos and county fairs, the government said Thursday in releasing new warnings about farm animal exhibits.

The Centers for Disease Control and Prevention cited E. coli outbreaks last year that sickened 56 people, including dozens of children, at a dairy farm in Pennsylvania and a petting zoo in Washington state.

The children touched goats, cows, chickens and other farm animals, then put their hands to their mouths - either by eating and drinking near the animals or by chewing their fingernails or sucking on pacifiers.

The CDC issued new guidelines for open animal exhibits, stressing that organizers should provide more adequate hand washing facilities and ban hand-to-mouth contact close to the animals.

``A lot of people go to these things,'' CDC epidemiologist John Crump said. ``There are people who are more susceptible to getting more serious illness, and those people are children.''

In Pennsylvania, 51 people - mostly children - became sick from E. coli last fall after visiting a dairy farm where the public can touch the animals. The CDC said sinks for washing were out of children's reach.

Last spring, four people became sick at the Washington petting zoo. A fifth was sickened after a sibling visited the zoo.

Nineteen of the 56 people were hospitalized. Symptoms of E. coli infection include fever, vomiting and severe diarrhea.

At the Pennsylvania farm - Merrymead Farm of Lansdale - owners are installing double fencing around animals and adding washing stations, spokesman Steve Quigley said.

But Quigley said concern should not be limited to animal farms and petting zoos.

``What happens when your neighbor wanders over and the child pets your dog without knowing it?'' he said. ``It's a national problem.''

The CDC said it was not concerned about everyday pets like dogs and cats carrying dangerous pathogens like E. coli. Crump said the government was compelled to issue its warning about farm animals because thousands of children visit petting zoos, traveling fairs and similar exhibits each year.

About 70,000 cases of E. coli infection are reported in the United States annually, about 100 of them fatal. Transmission usually comes through food and water, but exposure to animals is also a significant risk.

The guidelines issued Thursday also included posting information at exhibits about the risk of bacterial transmission, not serving raw milk, keeping food-and-drink areas separate from animal-contact areas and urging high-risk visitors like the elderly and pregnant women to use extra caution.

Copyright 2001 The Associated Press. All rights reserved.