How to avoid common stomach bug bacteria

Sweden is experiencing a rise in Campylobacter infections, particularly during the warmer months of June, July, and August. Microbiologist Catarina Flink from the Swedish Food Agency notes that the bacteria thrives in hot and humid conditions, making summer a peak season for outbreaks.

Campylobacter is a common intestinal bacterium found in various animals, especially poultry like chickens, but also in pigs, cattle, sheep, and unpasteurized milk. Humans typically contract the infection through contaminated food, often chicken, or via contaminated hands and kitchen utensils. Even a small amount of the bacteria can cause illness.

Symptoms usually appear two to five days after exposure and include severe stomach pain, nausea, fever, and sometimes bloody diarrhea. While most infections resolve on their own within a few days, complications like joint pain, chronic stomach issues, and nerve disorders can occur. To prevent spread, Flink advises rigorous kitchen hygiene: washing hands thoroughly with soap and water, disinfecting knives and cutting boards, and avoiding rinsing raw chicken under the tap, which can splash bacteria onto other surfaces.

Furthermore, it is essential to cook chicken completely to kill the bacteria. Campylobacter can also be transmitted through livestock, pets, or contaminated water. According to Sweden's Communicable Diseases Act, all confirmed cases must be reported to local infectious disease physicians. In 2025, Sweden recorded 5,463 cases, with a significant increase in domestically acquired infections noted in early June.