The Infectious Disease Epidemiology Annual Report provides a summary and assessment of notifications of diseases reported to the Robert Koch Institute (RKI). Another report has already shown the drop in reported foodborne outbreaks in 2020.

There was a large reduction of around 80 percent in some gastrointestinal diseases compared to before the COVID-19 pandemic. This was especially noticed for rotavirus gastroenteritis, shigellosis, and norovirus.

The pandemic affected the occurrence and detection of other notifiable diseases in a variety of ways, according to the report. The reasons for reductions are complex and different for each pathogen. As well as an actual decline in infectious diseases there are a number of factors related to coronavirus measures such as reduced travel and increased hygiene that may have led to changes.

In 2020, 423 potentially foodborne outbreaks (excluding norovirus) were reported to the RKI compared to 902 in 2019. Of the potential food outbreaks this past year, 160 were confirmed affecting 774 people.

Campylobacter and Salmonella results
Overall, 225 potential foodborne outbreaks of Campylobacter were reported with 515 patients compared to 387 outbreaks in 2019. A total of 97 foodborne outbreaks affected 236 people in 2020. The largest involved nine people and milk were listed as the suspected food category.

This past year, 46,519 Campylobacter cases were transmitted. The incidence was 24 percent lower than in 2019. Five people died due to illness. These were three men and two women between the ages of 78 and 87 years old.

Most infections were in Germany but some came from Austria, Croatia, Spain, Italy, France, and Poland as well as Morocco, Thailand, and India outside Europe. Incidence declined in all age groups except for 3 and 4-year-olds and in all but one federal state. Most cases were from June to September but a peak was also noted again at the start of the year.

In 2020, there were 109 possible food-related outbreaks of Salmonella with 592 cases versus 277 outbreaks in 2019. A total of 47 were confirmed in 2020 with 404 patients. The largest affected 161 people in several states. Dried coconut from Mozambique was found to be behind the Salmonella Muenchen outbreak after a case-control study and detection of the outbreak strain in food.

In total, 8,743 salmonellosis cases were recorded compared to 13,696 in 2019. Infections acquired outside Germany, Egypt, Turkey, Poland, and Thailand were most often mentioned. The highest age-specific incidence was in children under 5 years old.

The most frequently mentioned serovars were Salmonella Enteritidis and Salmonella Typhimurium (including the monophasic variant). Far behind were Salmonella Infantis, Muenchen, Derby, Brandenburg and Bovismorbificans.

Thirteen deaths were related to salmonellosis. These were seven men and six women aged 43 to 89. Four deaths each were attributed to Salmonella Typhimurium and Enteritidis, and one to Salmonella Infantis.

E. coli and HUS findings
There were 19 outbreaks of E. coli with 78 patients with the largest sickening 31 people. Three were listed as foodborne affecting 36 people.

Most outbreaks sickened two to four people and occurred in private households. The largest affected 31 people in four day-care centers supplied by the same caterer. Children, family members, staff, and employees of the caterer were affected with E. coli O26 confirmed for 16 people.

A total of 1,370 E. coli cases were reported which is a decrease of 27 percent compared to the previous year. Two deaths were noted in women aged 72 and 88.

The proportion of E. coli infections in which information on the serogroup was known was 15 percent in 2020, which is lower than in previous years. This information is important to identify any connections between infections that appear sporadic, said experts. The most frequently mentioned serogroups were O26, O157, O103, and O91.

The number of people infected abroad declined but Egypt, France, and Italy were mentioned most. As in past years, the incidence in children under 5 years old was much higher than in other age groups.

Sixty hemolytic uremic syndromes (HUS) illnesses were reported versus 73 in 2019. This fall is due to the decrease in the number acquired abroad. Three HUS-related deaths were recorded in a man and two women aged 67, 75, and 89 years old.

Three outbreaks each included one case of HUS and one to two cases of E. coli. In one affecting two adults and a child, raw donkey milk drunk on holiday in France was the suspected source of infection.

Incidence in children under 5 years old was higher than in other age groups. Eight HUS cases in children aged 5 to 14 and 11 in those aged 15 and over and adults were reported. As in the previous year, the serogroup O157 was listed the most at 10 times while O26, O111, and O145 were identified three times each.

Listeria and other diseases
In 2020, 11 Listeria outbreaks affected 56 patients. Three were foodborne with 39 sick. In one outbreak, 42 patients were infected from a common source. Nineteen women and 23 men aged 0 to 93 years with a median age of 80 were involved. There were two pregnancy-associated listeriosis cases and three people died. A smoked trout fillet from Denmark was identified as the likely food vehicle and after a product recall, infections declined.

In total, 575 listeriosis cases were recorded compared to 592 in the previous year. There were 31 deaths. Incidence increased with age with people above the age of 80 mainly ill.

In 2020, three foodborne botulism cases were reported compared to eight in 2019. All of them were acquired in Germany. It affected two women in their 50s and one man in his 60s. Two botulism toxin type E cases were linked to fish and one botulism type B to vegetables.

A total of 19 brucellosis cases were reported in 2020, 18 fewer than the previous year. At least nine people were infected in other countries including Iraq, Bosnia and Herzegovina, Turkey, Ethiopia, and Jordan.

In 2020, 557 hepatitis A cases were recorded, 316 fewer than in the previous year. The majority of those infected were not vaccinated. Two deaths in men above 60 years old were reported. Sixteen outbreaks were recorded with 79 patients. In one of these, 41 cases occurred in a local outbreak connected to a bakery.

RKI received 3,246 hepatitis E illnesses compared to 3,728 in 2019. Four deaths included two men and two women aged 48 to 74 years old. Four outbreaks affected eight people.

For Yersinia, 1,873 illnesses were reported in 2020 versus 2,171 in 2019. Most infections were in Germany. The age-specific incidence was highest in children under 5 years of age, with a peak among 1 and 2-year-olds. There were 10 outbreaks with 20 cases with five linked to food.

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