Impact of COVID-19 Restrictions on Incidence of Enteropathogenic Bacteria, Virus, and Parasites in Denmark: A National, Register-Based Study.

Abstract

Diarrheal diseases caused by enteric pathogens are a significant public health concern. It is widely considered that close contact between persons, poor hygiene, and consumption of contaminated food are the primary causes of gastroenteritis. Clinical microbiology laboratory observations indicate that the incidence of enteropathogenic microorganisms may have been reduced in Denmark during the COVID-19 pandemic. All Departments of Clinical Microbiology in Denmark provided data on the monthly incidence of Salmonella spp., Escherichia coli, Campylobacter spp., Clostridioides difficile, Norovirus GI+GII, Giardia duodenalis, and Cryptosporidium from March 2018 to February 2021. The data were divided into three periods as follows: Control Period 1 (March 2018 to February 2019); Control Period 2 (March 2019 to February 2020); and the Restriction (pandemic) Period (March 2020 to February 2021). The incidences of pathogenic Salmonella spp.-, Escherichia coli-, and Campylobacter spp.-positive samples decreased by 57.3%, 48.1%, and 32.9%, respectively, during the restriction period. No decrease in C. difficile was observed. Norovirus GI+GII-positive samples decreased by 85.6%. Giardia duodenalis-positive samples decreased by 66.2%. Cryptosporidium species decreased by 59.6%. This study demonstrates a clear decrease in the incidence of enteropathogenic bacteria (except for C. difficile), viruses, and parasites during the SARS-CoV-2 restriction period in Denmark.