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Zoonotic Diseases & Farm Animals

Zoonotic Diseases & Farm Animals

A zoonotic disease is a disease that can be passed from animals to humans. These diseases can be caused by viruses, bacteria, parasites, and fungi. Humans can contract zoonotic or vector-borne diseases through contact with an animal, its bodily fluids, its infected waste or its living environment; by contact with water or soil contaminated by infected animal waste; by eating meat from infected animals or eating food such as fruits and vegetables that have been contaminated by infected animal waste; or through vectors—such from infected animals to humans via mosquitoes, fleas or ticks. Following are some zoonoses related to farm animals, including cows, pigs, goats, and sheep:


Campylobacter is the most common bacterial cause of gastroenteritis worldwide and is prevalent in food animals such as cattle, pigs, and sheep. Symptoms include diarrhea, abdominal pain, fever, headache, nausea, and/or vomiting lasting 3-6 days. Transmission is food-borne via undercooked meats and meat products, as well as raw or contaminated milk. Ingestion of contaminated water or ice is also a source of infection. The only effective methods of eliminating Campylobacter from contaminated foods are through cooking, pasteurization, or irradiation. You can also prevent infection by avoiding contact with farm animals and their manure.

E. coli

Each year, Escherichia coli (E. coli) causes an estimated 73,000 cases of infection and 61 deaths in the United States. Infection often leads to bloody diarrhea, fever, abdominal cramps, nausea, and vomiting. Young children are more likely to have severe symptoms, including kidney failure. While most illness has been associated with eating undercooked and contaminated ground beef, it also can be passed in the manure of young calves and other cattle. Animals do not have to be ill to transmit E. coli to humans. The organism can be found on a small number of cattle farms and can live in the intestines of healthy cattle. Meat can become contaminated during slaughter, and organisms can be mixed into beef when it is ground. You can prevent E. coli infection by avoiding contact with cattle or their manure, by thoroughly cooking ground beef, avoiding unpasteurized milk, and washing hands carefully.


Salmonellosis is a bacterial disease. Typical symptoms include diarrhea, fever, and stomach pain that starts 1 to 3 days after infection. These symptoms usually go away after 1 week. In some cases, medical attention is required because the diarrhea is severe or the infection has affected other organs. Usually, people get salmonellosis by eating contaminated food, such as undercooked chicken or eggs. However, farm animals such as cattle, sheep, pigs and goats can carry Salmonella and pass it in their feces. If you have a compromised immune system, be extra cautious when visiting farms and animals at petting zoos.

To reduce infection risks, you should:

  • Cook meat, poultry and eggs thoroughly. Clean food preparation surfaces regularly. After preparing raw foods such as fish, meat or poultry, wash your hands, utensils and cutting boards.
  • Wash your hands thoroughly with soap and water after touching, feeding or caring for livestock and after cleaning up its waste.
  • Manure management and parasite/insect control programs are important. Humans can spread disease via boots, hands and tools. Proper disinfection protocols should be utilized to limit the risk of spreading disease.


  • Regular veterinary care is important for the health of every animal. Veterinarians are on the front lines of food safety, working to prevent and control disease—from caring for the health of a dairy herd to working in the food
    inspection process.
  • The best way to protect yourself from many of these zoonotic diseases is to practice good hygiene after handling animals or their waste. Wash your hands thoroughly with hot, soapy water after any contact. Always throughly cook any meat you intend to consume.
  • If you have any questions about these diseases or concerns about your animal's health, please consult your veterinarian. If you have concerns about your health, please seek medical attention from your health care provider.

Updated: June 25, 2019