Campylobacteriosis is an infection caused by the Campylobacter bacteria, recognized as one of the most common bacterial causes of diarrheal illness globally. The infection often results in gastroenteritis, characterized by diarrhea, abdominal pain, and fever. While typically self-limiting, its high incidence makes it a significant public health concern. Understanding how this bacterium spreads through food, water, and animal contact is the first step in prevention.
Primary Foodborne Pathways
The most frequent route of human infection is through the food supply, with raw or undercooked poultry being the largest contributor to cases. Campylobacter is highly prevalent in food animals, particularly chickens, and contaminates the meat during slaughter. A large percentage of raw chicken available in retail markets may be contaminated.
A surprisingly small number of bacteria can cause illness. Cooking chicken or turkey thoroughly to an internal temperature of at least 165°F is necessary to kill the bacteria and prevent infection.
Contamination also occurs through cross-contamination in the kitchen environment. Bacteria from raw meat, poultry, or seafood can be transferred to ready-to-eat foods like salads or fruits. Surfaces, cutting boards, utensils, and hands that touch raw poultry and are not cleaned properly serve as transfer points.
Raw or unpasteurized milk and dairy products represent another source of foodborne transmission. The bacteria can enter the milk through contact with manure or if the dairy cow has an udder infection. Outbreaks are frequently associated with consuming raw milk, which lacks the heat treatment necessary to kill germs. Other meats, such as beef, pork, and shellfish, have also been implicated when consumed raw or undercooked.
Environmental and Animal Contact Routes
Transmission routes outside of commercially processed food involve environmental sources or infected animals. Ingestion of untreated water is a common pathway, especially from contaminated wells, streams, or recreational water bodies. Water sources become contaminated when animal feces, particularly from wild birds or livestock, enters the supply.
Poorly maintained private water systems can also become contaminated, leading to outbreaks. Untreated or inadequately disinfected water poses a risk, as the bacteria are sensitive to standard water treatments. Recreational activities like swimming in contaminated lakes or rivers have also been linked to infection.
Direct contact with infected animals is a recognized zoonotic route. Farm animals (cattle, pigs, and sheep) carry the bacteria without showing illness. Humans are exposed through handling these animals or contact with their feces or environments.
Pets like dogs and cats can also transmit the bacteria. Puppies and kittens are noted for carrying Campylobacter, especially if they have diarrhea. Transmission occurs when people handle the pet or clean up its waste without practicing proper hand hygiene.
Direct Spread and Vulnerability
While most infections stem from food or environmental sources, person-to-person spread is possible. This transmission usually follows the fecal-oral route, occurring when microscopic amounts of infected feces are transferred from an ill person to another’s mouth. This is most often seen in settings where hygiene is difficult to maintain, such as daycare centers or households caring for someone with diarrhea.
Caregivers who change diapers or assist with toileting are at an elevated risk if handwashing is inadequate. Spread is likely because a relatively low dose of the bacteria is sufficient to cause infection in a new host.
Certain groups face a higher risk of severe illness once infected. Infants and young children under five are particularly vulnerable, as are adults aged 65 and older. Individuals with compromised immune systems also have a greater chance of experiencing serious complications. For these populations, the infection can potentially lead to rare long-term conditions, such as Guillain-Barré syndrome.
Preventing Infection
Effective prevention relies on simple hygiene and food safety practices. Since poultry is the main source, cook all chicken, turkey, and other poultry products thoroughly until they reach a safe internal temperature of 165°F. This heat treatment eliminates the bacteria from contaminated food.
Preventing cross-contamination is a primary kitchen practice. Raw meat and poultry must be kept separate from produce and ready-to-eat items during shopping, storage, and preparation. Use separate cutting boards for raw meat and clean all surfaces and utensils with soap and hot water after contact with raw products.
Consumers should only drink pasteurized milk and dairy products, as this process kills Campylobacter. Avoiding untreated surface water or water from questionable sources is also necessary. If drinking water safety is uncertain, boiling it or using a reliable disinfectant is recommended.
Frequent and thorough handwashing with soap and water remains the most effective way to break the transmission cycle. This is particularly important after handling raw meats, using the restroom, changing diapers, or after any contact with pets, farm animals, or their environments.