The number of foodborne outbreaks in Norway declined slightly this past year from 2018, according to the country’s public health agency.

In 2019, 223 outbreaks from all sources were reported with 5,401 cases of disease. This was the same level of outbreaks as in 2018, but there was an increase in cases because of a large waterborne outbreak in Askøy municipality in 2019.

Campylobacter jejuni was detected in patients and drinking water in June 2019. In total, 2,000 patients were estimated. Contamination was suspected to have been caused after heavy rainfall.

The number of notified foodborne outbreaks decreased from 52 in 2018. The Norwegian Institute of Public Health (Folkehelseinstituttet) reported that 46 outbreaks were because of suspected food or waterborne infections in 2019. They affected more than 2,700 people with a range of two to 2,000. More than 150 outbreaks were registered in health institutions and 20 were classed as “other.”

Norovirus cause of majority of outbreaks
The most common agents behind foodborne outbreaks were norovirus with 15, seven for Campylobacter and enterohemorrhagic E. coli infection with five. A total of 367 people were affected by norovirus outbreaks, 18 by EHEC and 2,026 for Campylobacter outbreaks.

Cryptosporidium was responsible for two outbreaks while Listeria, Staphylococcus aureus, Francisella tularensis that causes Tularemia, Clostridium perfringens, Shigella sonnei, Enteropathogenic E. coli (EPEC), Giardia lamblia, hepatitis A and Salmonella Agbeni all caused one outbreak each. Eighty-two people were part of eight outbreaks caused by unknown agents.

Cryptosporidium affected nine people, Listeria sickened six, 40 were ill with Staphylococcus aureus, 12 from Francisella tularensis and 14 by Clostridium perfringens. Shigella sickened 35 people, 25 got infections from EPEC, 13 Giardia, two were infected by hepatitis A and 56 patients were part of the Salmonella outbreak.

Restaurants, cafes, pubs, and fast food outlets were the places behind 16 outbreaks. Five each were traced to private households and canteens and four to catering businesses.

The food source was unknown for 29 of 46 outbreaks but seafood such as shrimp, crustaceans, mussels and mollusks were linked to three outbreaks and vegetables and herbs and drinking water both to two outbreaks.

Selected outbreak details
In September 2019, there was an accumulation of an EHEC serotype involving four people that had not previously been seen in the National Reference Laboratory database.  Samples from another four people were included in the outbreak investigation. Four of them developed hemolytic uremic syndrome (HUS). Despite all cases being interviewed and involvement of the Norwegian Food Safety Authority (Mattilsynet) the source was not found.

Attendees of a conference in the Bodø municipality that served different types of seafood at lunch and dinner were affected by a norovirus outbreak. A questionnaire was sent to the 250 participants and 39 people met the case definition. Norovirus was detected in one stool sample and found in samples from oysters served during the dinner.

During summer 2019, several outbreaks of norovirus were reported from different restaurants with more than 100 cases. In at least two of the incidents, norovirus was detected in patients. All the restaurants had received and served seaweed salad from one of two lots of Goma Wakame Seaweed salad produced by Dalian Kowa Foods Co. in China. Products were withdrawn and norovirus was detected in them. An outbreak of norovirus linked to seaweed salad from China was also reported by Spain in August 2019.

In December 2019, an outbreak of Shigella sonnei was linked to sugar peas, also known as sugar snaps, from Kenya. Twenty-eight employees at a company in Oslo who had eaten in the canteen were affected. No leftovers remained to be sampled but Shigella sonnei was detected in stool samples of seven employees. Mattilsynet recommends heat treatment of imported sugar peas before serving.

(To sign up for a free subscription to Food Safety News, click here.)