Petting Zoos Can Breed Illness

3 studies show bacterial infections from animal-to-human contact

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By Steven Reinberg
HealthDay Reporter

MONDAY, March 20, 2006 (HealthDay News) -- Petting zoos may be fun for the kids, but they are breeding grounds for bacteria that can cause severe gastrointestinal illness, new research contends.

Most people aren't aware that simple prevention measures such as handwashing could prevent infection, and some do things that might increase their risk, according to three new studies being presented Monday at the International Conference on Emerging Infectious Diseases meeting, in Atlanta.

Bacterial infection can result from touching anything that has come into contact with animal feces, including the animals themselves and surfaces that people have touched after petting the animals, eating or drinking while petting or feeding the animals, the researchers noted.

In addition, feces carried away on shoes can be taken home and become a risk for infection.

The first study deals with outbreaks of E. coli O157:H7 at two Florida petting zoos a year ago that sickened at least 34 people. The researchers, from the U.S. Centers for Disease Control and Prevention and the Florida Department of Health, interviewed visitors who did and did not get sick, to find out which behaviors predicted infection.

The behaviors most strongly associated with illness were feeding a cow or goat, touching a goat and stepping in manure or having manure on your shoes. Indirect contact that also led to illness included drying hands on clothes after washing them at the zoo.

Those who washed their hands after visiting the petting zoo, including lathering with soap and washing them again before eating, escaped illness, the researchers report.

In the second study, a team led by Amy E. Belflower, an epidemiologist at the South Carolina Department of Health and Environmental Control, watched 227 people in a petting zoo to see how many washed their hands or engaged in risky behaviors.

The petting zoos followed the guidelines, Belflower said. "They had the animals in pens, had signs about not bringing food and drink in, and lots of signs about washing your hands, and had good handwashing stations," she said.

"But even with all those precautions, we still saw people engaging in risky behavior," Belflower added. "The top three were bringing food into the area, bringing a stroller into the area, picking stuff like pet food off the ground. We also saw that 28 percent of the people who exited the petting area did not wash their hands."

In the third study, researchers from the Tennessee Department of Health and the U.S. Department of Agriculture also looked at how people behave in petting zoos.

Among 991 visitors to six petting zoos in middle Tennessee, they found that 49 percent of visitors touched their face while in the petting zoo, 87 percent came into contact with environmental surfaces such as handrails or benches, 74 percent touched animals, and 22 percent ate or drank while in the area. In addition, 62 percent did not wash their hands after leaving the petting zoo.

"There is a lot that can be done to educate zoo operators and the public," said lead author Marcy McMillian, an epidemiologist at the Tennessee Department of Health.

"People need to know that they need to do handwashing and that when they touch environmental surfaces and the animals, they are potentially exposing themselves to pathogens," McMillian said.

One expert questions the need for petting zoos at all.

"The problem is that the public is not aware of the dynamic of infection," said Philip M. Tierno, Jr., the director of Clinical Microbiology and Immunology at New York University Medical Center. "It's not just on your hands. So, even if you wash your hands, you are not assured that you can't pick it up."

Tierno warns against eating while in the petting zoo. "Even if you think you have washed your hands correctly, you may not have, and you will directly ingest E. coli," he said.

Correct handwashing, according to Tierno, involves washing your hands the length of time it takes to sing Happy Birthday twice. "You have to wash in between your fingers, the top of your hands and under the nail beds," he said.

Tierno believes that it's not a good idea to feed or pet animals in these zoos. "You have too many pathogens that can create problems in people. It's not worth it," he said.

Another expert thinks petting zoos are fine if visitors take the proper precautions.

"Children shouldn't be denied the joy of petting zoos," said Dr. David L. Katz, an associate professor of public health and director of the Prevention Research Center at Yale University School of Medicine. "After all, fraternizing with other people is also a potential source of bacterial contamination and potentially serious infection."

More information

The U.S. Centers for Disease Control and Prevention can tell you more about safety at petting zoos.

SOURCES: Amy E. Belflower, M.P.H., epidemiologist, South Carolina Department of Health and Environmental Control, Columbia; Marcy McMillian, M.P.H., epidemiologist, Tennessee Department of Health, Nashville; Philip M. Tierno, Jr., Ph.D., director, Clinical Microbiology and Immunology, New York University Medical Center, New York City; David L. Katz, M.D., M.P.H., associate professor, public health, and director, Prevention Research Center, Yale University School of Medicine, New Haven, Conn.; March 20, 2006, presentations, International Conference on Emerging Infectious Diseases, Atlanta

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