The number of most foodborne diseases dropped in Norway in 2020 but there were increases for Campylobacter, Cryptosporidium and Yersinia.

There was a decline for the majority of infectious diseases transmitted by food, water and animals and subject to notification in the Norwegian Surveillance System for Communicable Diseases (MSIS), according to the annual surveillance report published by the Norwegian Institute of Public Health (FHI).

The largest fall was for campylobacteriosis, salmonellosis, E. coli, hepatitis A, and giardiasis. The decrease is mainly because of fewer people being infected abroad, but also control measures in society as a result of the COVID-19 pandemic. However, there was an increase in domestic infections for Cryptosporidium, Campylobacter and Yersinia.

Higher domestic Campylobacter and Cryptosporidium figures
Overall, 2,422 Campylobacter infections were reported compared to 4,155 in 2019. Of the 2020 patients, 1,513 cases were infected in Norway and 262 abroad while this information was not known for the rest. Of those sick abroad, most were infected in Thailand, Spain and Pakistan.

Among people infected in Norway, those hospitalized included 665 women and 846 men. This proportion is higher than previous years. Most domestic cases were reported in July and August.

Officials said one explanation for this is that fewer people went to the doctor because of the pandemic, so only those with more serious symptoms were diagnosed. Another is that many spent the summer outside in Norway because of travel restrictions which could have increased the use of water with poor quality and contact with livestock.

Cryptosporidium went up from 378 to 483 in 2020. Overall, 352 people were infected in Norway, 17 abroad, and this was unknown for 114 patients. More than 100 were hospitalized.

Most cases were reported in August, November and September. The majority of patients were in the age groups 30 to 39 years old, 0 to 9 and 20 to 29.

Domestic acquired infections rose, which officials said could be because of improving diagnostics and the fact that more people spent the summer in Norway because of COVID-19 travel restrictions and were more exposed to poor quality water and had more contact with animals.

Large dro in E. coli and Salmonella infections
In 2020, 331 E. coli cases were recorded; this is a decrease compared to 511 in the previous year. Of these, 207 were infected in Norway, 28 cases abroad, and for 96 this information was not stated.

Most cases were reported in July, January and August. The age groups 0 to 9 years old, 20 to 29 and 10 to 19 were the most affected. The top serogroup was O103, followed by O26 and O146.

E. coli infection led to hospitalization for 95 patients, most aged 0 to 9 years old. Four developed the serious complication hemolytic uremic syndrome (HUS), including three children with one child dying. Serogroups were O157, O26 and O145.

Salmonella infections declined from 1,904 in 2019 to 440 with 178 hospitalizations. In 2020, 172 cases were infected in Norway, 176 abroad, and this was not known for 92 people. The top countries of infection were Spain, Thailand and Indonesia.

Most cases were reported in February, January and March. The majority of patients were in the age groups 60 to 69 years old, 50 to 59 and 0 to 9.

Salmonella Enteritidis was by far the most common type followed by Salmonella Typhimurium, Newport and Stanley.

Listeria and Yersinia data
Listeria cases went up to 37 from 27 in 2019 and all were hospitalized. In total, 18 were women and 19 were men.

The most cases were in the age groups 70 to 79, 80 to 89 and 60 to 69. Most cases were reported in December, September and June.

only one outbreak of listeriosis was recorded in 2020, which included four patients but the source was not found.

Yersinia stayed around the same level with 83 in 2020 compared to 85 the year before. A total of 66 cases were infected in Norway, three were sick abroad, and for 14 this data was not stated.

Most cases were reported in January, May, June and November. All but one was caused by Yersinia enterocolitica and 27 people were hospitalized. Patients were mainly in the age groups 20 to 29 years old, 0 to 9 and 30 to 39.

There was a decrease in the number of patients infected abroad, while domestic infections increased. This is primarily because of three outbreaks.

In 2020, two domestic cases of botulism were reported. The suspected source of infection was homemade rakfisk, a traditional Norwegian fermented fish product.

Fourteen cases of hepatitis A were noted with half infected in Norway, three abroad, and it was not known for four patients. All were adults aged 30 to 59 and eight people were hospitalized.

For Shigella, 37 cases were reported and 18 people were hospitalized. This is far lower than the 133 patients in 2019 and was attributed to restrictions on international travel during the pandemic leading to fewer infections from abroad.