Up to 100 people could be affected by an ongoing Campylobacter outbreak on a Danish island.

The Danish Veterinary and Food Administration (Fødevarestyrelsen), DTU Food Institute and Statens Serum Institut (SSI) are investigating the outbreak that began in Bornholm in early June.

The alarm was first raised by Bornholms hospital and now there are reports of 100 people with symptoms similar to a Campylobacter infection with at least 10 of them needing hospital treatment.

So far, 54 people aged 9 months to 97 years old have tested positive for Campylobacter and other patient samples are being studied. Those sick live on Bornholm or visited the island recently.

While a specific source of the outbreak is still under investigation the cause is suspected to be a locally produced food, presumably a ready-to-eat product.

Campylobacter is the top cause of gastrointestinal infection in Denmark. In 2019, more than 5,300 cases were registered, which is the highest number ever recorded and up from 4,500 in 2018. Around a third of the cases were infected abroad.

ongoing investigations
Bornholms hospital received reports of fever, diarrhea, and general malaise after Pentecost, a Christian holiday and festival. More than 10 people were admitted to the hospital with symptoms and analysis showed they had Campylobacteriosis.

SSI is in the process of contacting patients and asking them what they ate and drank in the days before becoming ill. The agency is also doing interviews with a control group of healthy citizens and investigating if it is the same type of Campylobacter that has made people sick through the use of whole-genome sequencing.

The Danish Veterinary and Food Administration is visiting local producers on the island and taking samples of food for microbiological analysis to identify the source and stop the outbreak.

Nikolas Kühn Hove, from Fødevarestyrelsen, said several sources are being investigated.

“It is important that, as a consumer, you follow Fødevarestyrelsen’s general hygiene advice to wash fruit and vegetables, thoroughly cook chicken meat and keep raw meat separate from food, such as salad, bread, and cooked meat.”

Undercooked poultry is a common cause of infection with Campylobacter but other sources may include unpasteurized milk, contaminated fruits, and vegetables or drinking water, and contact with animals and pets.

People with Campylobacter infection usually have diarrhea, fever, and stomach cramps. They may also have nausea and vomiting. These symptoms usually start two to five days after the person ingests Campylobacter and lasts about one week.