How Campylobacter is Transmitted from Animals to Humans

Campylobacter is a type of bacteria that can infect the intestines, and perhaps blood, of people and animals causing campylobacteriosis. This illness will cause symptoms like nausea, fever, vomiting, stomach pain, and mild to severe diarrhea. The transmission of campylobacter will likely occur between animals and humans and may be the result of several different pathways.


Every year about 2.4 million people will become infected by campylobacter. It is actually one of the leading causes of food related or food-borne illness and diarrhea. Those commonly affected by this bacterium include young adults, teenagers, and babies usually under the age of one. This infection can easily be transmitted if a person is not cautious, do not take any preventative measures, or possibly because they are not even aware of this bacteria.

Many people who become infected with this bacterium will likely not realize it and most cases will go unreported. In people with a weakened immune system, it is possible for campylobacter to spread to bloodstream and lead to life-threatening infections. About 124 people each year will die as a result from complications because of this infection.

Transmission of campylobacter

Campylobacter can be present in the intestines of a variety of animals including cows, chicken, sheep, pigs, dogs, cats, and even people. The transmission of campylobacter from one species to another or between species can occur as a result of several different reasons. However the primary method of infection is through ingestion of contaminated materials.

When an animal is slaughtered, there is the possibility that campylobacter that was present in the intestines of the animal may contaminate the meat of the animal. Should the meat not be properly cooked, there is a chance of the contamination spreading to people. Cross-contamination may also occur from a contaminated food to a non-contaminated food in a kitchen or where the meat is prepared. In fact, contamination is greater through cross-contamination of other foods during food preparation than through the originally contaminated meat. This is due to not all foods being cooked like meat will be. Foods like vegetables may be cut on the same surface as the meat or with the same utensil but be cooked nearly as thoroughly as the meat, which would allow for possible contamination. 

Besides poultry and meats, other common sources or pathways of campylobacter contamination involve fecal matter. Handling contaminated fecal matter of humans, pets, or livestock can result in accidental digestion if hands are not properly washed after contact. Sometimes pets or livestock will have small amounts of fecal matter stuck in their fur and people can come into contact with this material without even realizing it. Babies that are infected with campylobacter can infect others as a result of diaper changes.

Water can also contain campylobacter if fecal matter from humans or animals contaminates a water body (lakes, rivers, streams) or a well. Ingestion or drinking of water that is contaminated will result if the water is not treated. Contamination can also occur as a result of drinking unpasteurized milk or eating/drinking unpasteurized milk containing products.


Because it is not always known if the food you buy or the animals you raise are contaminated, it is always good to be on the safe side. Thoroughly cook meats and avoid cross contamination between other foods and the meat. Frequently washing hands before a meal or after contacting possibly infected animals is also a good way to limit the possibility of being infected with campylobacteriosis. Using protective measures or even just gloves when possibly handling fecal matter is a good way to reduce the risk of contamination as it will not get on your hands. Getting well water checked and not swimming or drinking from a water source that could be contaminated can also prevent infection.