Pandemic restrictions lead to fewer cases of foodborne illness

In 2020, far fewer Danes than usual were diagnosed with a foodborne illness. The sharp reduction in travel during the corona epidemic was the main reason for this decrease, according to the annual report on the incidence of zoonoses in Denmark.

2020 was in many ways an unusual year. This is also evident when reading the annual report on the incidence of zoonoses in Denmark. The report was prepared by the National Food Institute, Technical University of Denmark, in cooperation with Statens Serum Institut (SSI) and the Danish Veterinary and Food Administration. Zoonoses are diseases that can be transmitted from animals and food to humans.

In line with previous years, campylobacter bacteria were the leading cause of foodborne illness cases in 2020. However, 31% fewer campylobacter cases were recorded in 2020 compared with the previous year. In the same way, salmonella infections—which are the second leading cause of foodborne illness in Denmark— decreased by 45%.

Less travel leads to fewer infections

For many years, a large number of registered infections have been an unwanted souvenir from a trip abroad. The significant reduction in travel during 2020 is indeed the primary reason for the sharp decrease in the number of cases. The decrease can also be attributed to the fact that Danes were less likely to visit the doctor with minor illness symptoms during the spring lockdown.

"In addition to the changes in Danes' travel patterns and the reduced number of doctor's visits that were bought about by the COVID-19 epidemic, the overall corona restrictions such as the closure of restaurants and canteens contributed to the decrease in registered foodborne illness cases in 2020," epidemiologist Luise Müller from SSI says.

Better methods help produce accurate data

It is well known that many Danes who get sick from something they have eaten never become part of the official statistics. This could be due to them not visiting the doctor or because the doctor doesn't get a sample that can be submitted for diagnosis.

Without solid data to show how many Danes actually get a foodborne illness, it becomes harder for the authorities to decide where best to intervene to ensure that consumers have access to safe foods and that as few people as possible become sick from the food they eat.

"In order to ensure more accurate data, we continue to apply methods that can correct for underreporting and underdiagnosing—such as during a pandemic—which will allow us to calculate the real burden of disease for various diseases," senior researcher Sara Monteiro Pires from the National Food Institute says.

The annual report presents a large amount of data collected by authorities and the industry in Denmark on the incidence of zoonoses in feed, animals, food and humans. Many of the tables include datasets that span more than ten years and as such provide an opportunity to follow trends over time.

Find the full report on the National Food Institute's website: Annual Report on Zoonoses in Denmark 2020 (pdf). You can also have the printed report sent to you by contacting Vibeke Dybdahl Hammer, vdha@food.dtu.dk.

This year's Annual Report does not contain a Salmonella source account due to challenges relating to data management. The authors expect to publish the source account in the third quarter of 2021.

The 2020 report in numbers:

• A total of 35 foodborne outbreaks were registered compared with 51 outbreaks the previous year. In particular, the number of outbreaks related to norovirus decreased, from 19 outbreaks in 2019 to six outbreaks in 2020.
• Four bacteria were the main cause of registered illness cases: Campylobacter (3,742), salmonella (614), STEC (448) and Yersinia enterocolitica (413).
• In the report, the burden of disease related to six foodborne illnesses has been calculated based on 2019 data. At a population level, the burden of disease is greatest for campylobacter, which affects many Danes, but most often triggers illness with relatively mild symptoms. At the individual level, it is highest for Listeria monocytogenes, which affects only a very small number of people, but has a very high mortality rate.