Danish officials are investigating an E. coli outbreak that has 26 cases with three out of four being children.

Statens Serum Institut (SSI), the agency responsible for the preparedness against infectious diseases in Denmark, said the source of infection is not yet known but an investigation is under way.

SSI told Food Safety News that the 26 confirmed patients’ ages are between less than 1 year old to 95 years old, with 19 being children younger than five years of age. One person has been hospitalized. No deaths have been reported.

Cases with a specific type of Shiga toxin-producing E. coli (STEC) or Verotoxigenic E. coli (VTEC) have been reported to SSI in the past few weeks.

E. coli O26:H11 illnesses are spread across the country, but are primarily in the cities of Copenhagen, Aarhus and Odense. Illness onset dates range from Aug. 23 to Oct. 10.

From 2015-17, this O-group of E. coli was usually among the top four in terms of number of episodes in the country. The other E. coli bacteria in the top spots were O157, O103 and O146.

Interviews to find the source of infection with cases or their parents are ongoing with Fødevarestyrelsen (Danish Veterinary and Food Administration) and DTU Fødevareinstituttet (DTU Food – National Food Institute).

SSI said it had shared information with the European Centre for Disease Prevention and Control (ECDC). No other countries have confirmed cases related to the outbreak in Denmark.

The outbreak strain causes relatively mild symptoms in most patients. It harbors the Shiga toxin (stx) 1a gene while hemolytic-uremic syndrome (HUS) is more often associated with strains that produce Stx2a. HUS is a severe complication of E. coli infection that can lead to kidney failure.

The strain is resistant to ampicillin, trimethoprim and sulfamethoxazole. Such mild diarrhea cases normally don’t need to be treated with antibiotics, but if they were these antibiotics would likely not be the first choice of medical practitioners.

STEC is destroyed by cooking food until all parts reach a temperature of 70 degrees C or higher. Symptoms include abdominal cramps and diarrhea. The incubation period can range from three to eight days and most patients recover within 10 days. People at higher risk of severe infections, life-threatening complications and death include young children, frail and elderly people, pregnant women, and people such as cancer patients and pregnant because they have mature or weakened immune systems

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