A large decline in the disease burden of 14 pathogens in the Netherlands in 2020 has been attributed to the COVID-19 pandemic.

The National Institute for Public Health and the Environment (RIVM) analyzed how many years are lost on average because of ill health or death as a result of gastrointestinal illness and the cost of the disease burden.

The 14 pathogens causing infections are primarily foodborne. They are Campylobacter; Shiga toxin-producing E. coli (STEC) O157; Salmonella; Listeria monocytogenes; Toxoplasma gondii; hepatitis A and E viruses; Bacillus Cereus; Clostridium perfringens; Staphylococcus aureus; norovirus; rotavirus; Cryptosporidium; and Giardia.

Burden of disease was much lower in 2020 than 2019. This is probably because of measures in the Netherlands since March 2020 to stop the spread of the COVID virus, according to the report.

Examples of such actions include closure of restaurants and cafés, a ban on face-to-face meetings, restrictions on international travel, and an increased focus on hygiene, including handwashing. Fewer people might have sought or received medical help for foodborne illnesses, which require a laboratory diagnosis and other things, to be registered.

Half of burden from food
Disability Adjusted Life Years (DALYs) are used to quantify the disease burden. The estimated burden via food in 2020 was 3,600 DALYs, which was down from 4,600 DALYs in 2019. For the 14 pathogens combined, the number of DALYs was 7,300, which is much less than the figure for 2019.

A decrease in burden was seen for Campylobacter, Salmonella, norovirus, rotavirus, hepatitis A and E viruses, Cryptosporidium and Giardia spp. Top was Campylobacter, followed by Toxoplasma gondii and Salmonella.

The estimated number of cases attributed to the 14 pathogens decreased from 1.57 million in 2019 to 963,000 in 2020 with 553,000 infections and 76 deaths linked to food.

Cost of this disease burden in 2020 was estimated at €282 ($318) million overall, which was  less than €423 ($477) million in 2019. Estimates include the direct medical costs in hospitals, as well as those incurred by patients and families, such as travelling expenses. It also covers costs in other sectors such as a result of being off work.

Pathogens causing the largest cost of illness were Staphylococcus aureus toxin, norovirus and Campylobacter. The main changes compared to 2019 were all down and were for norovirus, rotavirus and Campylobacter.

The lowest contribution to cost of illness was by hepatitis A virus at €400,000 ($451,000). Average cost per case was most for perinatal Listeria monocytogenes infections with €292,000 ($329,000).

Foodborne disease part of costs
Contribution of the foodborne pathway accounted for more than half of the burden compared to about 43 percent in 2019. This is also an effect of the pandemic, as international travel declined so there was an increase in the relative importance of other sources, according to the analysis.

Costs resulting from contaminated food decreased to €153 ($172) million compared to €181 ($204) million in 2019. The largest contributor was Staphylococcus aureus followed by Clostridium perfringens and Campylobacter.

about 61 percent of the foodborne burden was associated with meat such as poultry, pork, beef and lamb. These products caused almost half of all food-related deaths. Dairy, fish and shellfish and grains also contributed to the burden.

From 2019, the burden of disease and cost of illness for toxin-producing bacteria Bacillus cereus, Clostridium perfringens and Staphylococcus aureus were not estimated because of a lack of national surveillance data. However, they were included in the overall estimates using past data to ensure comparability with previous years.

For Cryptosporidium and Giardia, no up-to-date incidence data at the national level were available for 2020. For Toxoplasma gondii there was no trend information but an updat to incidence estimates is planned in the coming year.