Colorado State University Extension
SafeFood Rapid Response Network
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HEALTHY PETS, HEALTHY PEOPLE
Edited by: Stephanie Wallner, M.S., Mary Schroeder, M.S., R.D, Pat Kendall, Ph.D., R.D., Colorado State - Fall 2006
Pets are an important part of life for many people. According to the American Pet Products Manufacturers Association, Americans own over 77 million cats, 65 million dogs, 17 million birds, and 9 million reptiles as pets. That's more than one pet for every two humans in the U.S! As temperatures warm and days get longer, animal lovers take advantage of outdoor activities with their pets. 
This can be a great way for families to interact and get exercise; however, as we spend more time with household pets it is important to remember that domestic animals sometimes carry diseases that can be transmitted to humans.
Zoonotic diseases, or zoonoses, are diseases that animals carry and transmit to humans. Some types of animals are more likely than others to carry and spread zoonoses, including baby chicks, ducklings, monkeys, turtles, lizards, snakes, and other reptiles. There are many different types of zoonoses, with new ones emerging as international travel becomes more common and people unintentionally carry diseases home with them. For example, the first known human outbreak of monkeypox was reported in the United States in 2003; the disease was likely carried into the U.S. with a shipment of rodents and other small mammals imported from Africa. These animals infected prairie dogs sold as pets, which in turn infected their pet owners. Following this outbreak, the Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) began a ban on imports of rodents from Africa in an effort to control additional cases of monkeypox in the U.S.
Although anyone can get a disease from their pet, those most vulnerable include the elderly, pregnant women, infants and young children, and persons with compromised immune systems due to disease. Diseases may be spread from pets to humans through parasites, bacteria, fungi and viruses. Here are a few of the most common culprits for pets and the people who come in contact with them.
Worms. Worms can easily infect dogs and cats - 90% of all puppies are born with worms. If left untreated, worm eggs will be passed through the pet's feces and may contaminate areas of the home and yard. Children are at especially high risk for contracting worms if they walk barefoot, play in the dirt, or touch their mouths after playing outside. Even playing on the floor where a dog may have tracked in dirt or feces may be a route for transmission of worms to infants and young children. To help prevent worms, full grown animals should be tested annually by a vet and should be treated with deworming drugs if necessary.
Toxoplasmosis. Toxoplasma gondii is a parasite, often carried by cats, that causes toxoplasmosis. Humans can get toxoplasmosis by contact with cat feces, eating raw or undercooked meat, and gardening or handling soil infected with the parasite. It is estimated that millions of people in the U.S. carry the parasite, but most do not become ill. Toxoplasmosis is mainly a danger for pregnant women, as it can cause serious illness, miscarriage, and birth defects in newborns. Pregnant women and other persons with compromised immunity should avoid undercooked meat and handling cats and cat litter boxes to reduce the risk of illness from this parasite.
Salmonellosis. Salmonella is a type of bacterium that causes salmonellosis. While the most common cause of salmonellosis is eating raw or undercooked meats or eggs, the disease can also be directly transmitted through contact with pet feces, particularly that of reptiles, chicks, and ducklings. In fact the CDC estimates that 70,000 Americans become ill with salmonellosis each year from contact with pet reptiles. Therefore, people who keep these animals as pets should clean cages thoroughly and always wash their hands after handling pets.
With all types of diseases carried by animals, it is important for parents to remember that infants and children under the age of 5 years are especially susceptible to becoming ill. Young children often like to touch animals, play outside in dirt or soil, and touch their faces or mouths - which can lead to illness from zoonoses. In recent years, several outbreaks of illness from animal diseases have been linked to dairy farms and petting zoos where children have close contact with animals. In these settings, it is especially important to supervise children and make sure their hands are washed thoroughly after contact with any animals or soil. Although the risk of contracting zoonoses is small for most healthy people, illness can be avoided by practicing proper hygiene after handling animals, keeping pets and pet play areas clean in the home, and having pets vaccinated and examined by a vet on a regular basis.
For more information on animal diseases, the following references are available:
- Centers for Disease Control and Prevention. Healthy Pets Healthy People. Available at: http://www.cdc.gov/healthypets/.
- Centers for Disease Control and Prevention. Outbreaks of Escherichia coli O157:H7 Associated with Petting Zoos --- North Carolina, Florida, and Arizona, 2004 and 2005. Morbidity and Mortality Weekly Report. 2005;54(50):1277-1280.
- Colorado Department of Public Health and Environment. State Health Officials Remind Parents that Baby Chicks and Ducks can Carry Salmonella. Available at: http://www.cdphe.state.co.us/release/2006/040706.html.
- Food and Drug Administration (FDA). Keeping Pets (and People) Healthy. Available at: http://www.fda.gov/fdac/features/2004/104_pets.html. Accessed April 14, 2006.
