Chickens and other poultry, whether kept in a backyard flock or raised commercially, host various pathogens that can be passed to people, a process known as zoonosis. While the presence of these organisms is common, the risk of human infection is manageable through awareness and proper hygiene. Understanding the specific diseases and their transmission routes is the most effective way to protect public health.
Common Bacterial Infections Transmitted by Poultry
The most frequent health threats humans acquire from poultry are bacterial, primarily involving the digestive tract. Salmonella is one of the most widely known concerns, residing naturally in the intestines of many animals, including chickens. Transmission to humans commonly occurs through the fecal-oral route, either from direct contact with a bird’s droppings or indirectly via contaminated surfaces, coops, or raw and undercooked meat and eggs.
Symptoms of salmonellosis typically include diarrhea, fever, and abdominal cramps, generally appearing 6 hours to 6 days after infection. While most healthy adults recover without specific treatment, the infection can be severe for certain populations. Children younger than five, adults over 65, and individuals with compromised immune systems face a higher risk of developing severe illness or complications requiring hospitalization.
Another major bacterial pathogen is Campylobacter, which is the leading cause of bacterial gastroenteritis globally. Chickens are highly efficient hosts for this bacteria, and contaminated poultry meat is a primary source of human infection. In humans, campylobacteriosis causes symptoms like diarrhea, fever, and muscle pain, often lasting about a week.
Escherichia coli (E. coli) can also be found in poultry. Like Salmonella, the main transmission route for E. coli is through consuming raw or undercooked poultry products or through cross-contamination in the kitchen.
Viral and Other Less Common Threats
Chickens can transmit less frequent pathogens that affect different body systems. Avian Influenza, commonly known as Bird Flu, is a viral concern. Human infection is rare and usually requires close, prolonged, and unprotected contact with sick or dead infected birds or their heavily contaminated environments.
The virus primarily affects the respiratory system, and while human-to-human transmission is not typically sustained, the mortality rate in confirmed human cases can be high. Avian Influenza transmission often involves exposure to respiratory droplets, aerosols, or environments contaminated by the feces of infected birds.
A different type of threat is Psittacosis, a respiratory illness caused by the bacterium Chlamydia psittaci. Although often associated with parrots, it can be transmitted to humans from poultry like chickens and ducks. Infection occurs when a person inhales aerosolized bacteria from the dried feces, respiratory secretions, or feather dust of an infected bird. Symptoms often resemble a severe flu, including fever, headache, muscle aches, and a dry cough, sometimes progressing to pneumonia.
A fungal illness, Histoplasmosis, is connected to poultry. It is caused by inhaling spores of the fungus Histoplasma capsulatum, which thrives in soil heavily enriched with bird droppings, particularly in old chicken coops. Histoplasmosis is primarily a lung infection that can cause flu-like symptoms such as fever and chest pain, though many exposures result in no symptoms at all.
Essential Safety Measures and Prevention
Mitigating the risk of zoonotic disease transmission from poultry centers on rigorous hygiene and food safety practices. Handwashing is the most effective barrier; hands must be washed thoroughly with soap and water for at least 20 seconds immediately after handling raw poultry, eggs, or any part of a bird’s environment. Dedicated footwear and clothing should be used when tending to backyard flocks or coops, and these items should be left outside the home to prevent tracking contaminants indoors.
In the kitchen, preventing cross-contamination is paramount to avoiding bacterial spread. Raw chicken and its juices should be kept physically separate from all ready-to-eat foods, such as salads or cooked meals. It is recommended to use a separate cutting board specifically for raw meat and to clean all utensils and surfaces with hot, soapy water after contact.
Washing raw chicken should be avoided because it splashes bacteria-containing juices onto sinks, countertops, and nearby foods. Bacteria are only reliably destroyed by heat, making proper cooking the final defense. Poultry, including ground products, must be cooked to a minimum safe internal temperature of 165°F (74°C), verified using a food thermometer. Eggs should also be handled carefully, and cracked eggs should be discarded.