Norovirus is behind most outbreaks and illnesses in Sweden

According to the Swedish Food Agency (Livsmedelsverket), norovirus caused the most outbreaks and illnesses in 2022.

Overall, the agency received 337 reports of suspected or confirmed foodborne illness, with 2,261 cases. In 303 incidents, two or more people were infected from the same source. This is an increase from 251 outbreaks and 1,467 patients in 2021.

In 2022, food poisoning numbers returned to pre-COVID-19 pandemic levels. The increase in outbreaks and illnesses began in late 2021, when many of the restrictions put in place during the pandemic were lifted.

The number of incidents peaked in the last six months of 2022. This is because four large outbreaks occurred in September and December, involving more than 100 patients.

Most outbreaks are caused by norovirus

Eight reports said 45 people required hospitalization. One person died in a listeriosis outbreak caused by pâté/cold-smoked salmon.

There were 273 reported outbreaks of unknown origin. However, 24 outbreaks (544 cases) were caused by viruses, 22 outbreaks (334 cases) were caused by bacteria, 6 outbreaks (208 cases) were caused by parasites, and other outbreaks such as histamine or lectins The cause is linked to 12 outbreaks (68 patients).

Norovirus was the pathogen causing the most outbreaks, with 23 and 536 cases respectively. Nine outbreaks have been linked to seafood such as oysters and mussels. 10 histamine incidents affected 30 people. Six Cryptosporidium epidemics sickened 208 people. Salmonella was behind eight outbreaks, sickening 193 people.

Listeria, Campylobacter, Escherichia coli, Staphylococcus aureus and Bacillus cereus, hepatitis A, Clostridium perfringens and Yersinia enterocolitica have also caused outbreaks.

The most affected categories were vegetables (263 cases) and buffet foods (236 cases).

Eggs from Sweden were the source of the salmonellosis outbreak, which is unusual, the report said. The company, CA Cedergren, is still only allowed to sell eggs to other food companies, which must heat-treat the eggs before using them in any products. Earlier this year, the Swedish Public Health Agency (Folkhälsomyndigheten) reported an outbreak of Salmonella Enteritidis that sickened 79 people.

outbreak factors
Thirty reports noted that the most common factor contributing to outbreaks was “staff infection/poor hygiene.” This means the person handling the food is a carrier or is not following good hygiene practices. The second is “high temperature in cold storage”, which was mentioned 26 times.

Several histamine incidents have been linked to cacti, which often come from Asian countries. One salmonella outbreak has been linked to cucumbers from Spain, while another outbreak is suspected to have been caused by ground meat from Poland. The salmonella outbreak was linked to rocket salad, and the norovirus oyster outbreak was linked to food produced in Sweden.

A previous report found that most foodborne infections increased in Sweden in 2022 compared with the previous year.

As October 2023 begins, the Swedish Public Health Agency has revealed that there has been an increase in Campylobacter cases over the past two weeks. There has been an increase in reported cases compared to the same period last year, with infections reported in all 21 districts.

In September, the agency said the number of reported cases continued to remain high in August, with an average of 140 infections per week. However, September’s numbers were comparable to the same period in 2022.

After the summer, the number of reported cases remains high. As the number of Campylobacter bacteria increases in broiler flocks, so does the number of patients.

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