Campylobacter infection is a common bacterial illness caused by the Campylobacter bacteria, often found in undercooked poultry, unpasteurized milk, and contaminated water. Symptoms typically include diarrhea, abdominal pain, fever, and nausea, which usually appear within two to five days after exposure. Most people recover without treatment, but severe cases can lead to complications, especially in young children, the elderly, and those with weakened immune systems. Preventive measures include cooking meat thoroughly, practicing good hygiene, and avoiding unpasteurized dairy products to reduce the risk of infection.