Netherlands records more than 700 outbreaks in 2019

More than 700 food-related outbreaks were reported in the Netherlands in both 2018 and 2019.

In 2018, 756 foodborne outbreaks with 2,805 illnesses were recorded and in this past year 735 outbreaks with 3,058 illnesses were reported. The number of outbreaks went up from 2017 but illnesses declined.

The data comes from an overview by the National Institute for Public Health and the Environment (RIVM) of the main zoonoses and their prevalence in the country for the Netherlands Food and Consumer Product Safety Authority (NVWA). It features 2018 and 2019 figures. The NVWA did not report 2018 outbreak data in 2019 because of a technical issue.

Most outbreaks involved two to four people, followed by five to nine patients. However, in 2018, there were four outbreaks with 35 or more sick, ranging from 38 to 132. In 2019, there were 11 major outbreaks with 35 to 100 sick. A pathogen was reported in only 6 percent of outbreaks, so 44 in 2018 and 42 in 2019. It was mostly found in patients and sometimes in food and/or environmental samples.

Agent responsible for outbreaks
Norovirus was the main cause of outbreaks with 16 and 17 in 2018 and 2019, respectively, and most patients in both years with 370 and 375. The number of outbreaks is lower than 2017 but higher than 2016.

In 2018, there were more Campylobacter outbreaks at 13 than Salmonella outbreaks at seven. In 2019 this was exactly the other way around. In both years there were more Salmonella patients — 50 in 2018 and 148 in 2019 — than Campylobacter, which had 30 and 17, respectively.

Two Salmonella outbreaks with more than 50 reported cases were caused by eggs. Two other outbreaks saw patients linked by whole genome sequencing to pig carcasses from a slaughterhouse in 2018 and slaughterhouse samples and imported chicken in 2019.

Listeria monocytogenes was reported three times in 2019, one of which was the outbreak linked to processed meats from Offerman that caused 35 illnesses from 2017 to 2019. Histamine also caused three outbreaks, two in 2018 and one in 2019. One was traced to tuna. Staphylococcus aureus was found in a vegetable dish in 2018.

Hepatitis A and Shiga toxin-producing E. coli (STEC) were both behind two outbreaks in 2018. Giardia was responsible for one in both years and the parasites Dientamoeba fragilis and Blastocystis hominis caused one outbreak in 2019.

Campylobacter and Listeria on increase
In 2017, the lowest number of laboratory-confirmed cases of campylobacteriosis since the start of registration in 1993 was found. However, it increased in 2018 and again in 2019.

It is estimated that in 2019 there were 6,077 nationally lab-confirmed cases compared to 5,944 in 2018 and 5,557 in 2017. The 2019 figure is based on 3,530 reports in a system that has an estimated coverage of 58 percent of the population. The previous system had a coverage ratio of 52 percent.

Estimated cases of illness due to Campylobacter infections in 2019 was 72,967 compared to 71,246 in 2018 and 67,260 in 2017. This would put the cost of illness at €62 million (U.S. $73 million).

In 2019, there were 117 listeriosis patients reported. Along with 2017, it is the highest rate since introduction of the notification requirement at the end of 2008. Four patients were pregnant in 2019 at the time of infection. Fifteen patients, aged 57 to 94, died. Infections were linked to sausage products, cooked or smoked ham and chicken and turkey meats.

In 2019, Wageningen Food Safety Research, commissioned by NVWA, examined 3,400 batches of food quantitatively and 2,700 samples qualitatively for Listeria monocytogenes. A total of 167 isolates were found with most from fish including salmon, trout, herring, mackerel, and shrimp. Fresh poultry was second followed by fresh beef, meat preparations to be consumed raw, one isolate from kangaroo meat and five from imported poultry. Two isolates came from raw milk.

Salmonella situation
In 2019, the 1,002 Salmonella isolates submitted from patients in the Netherlands was slightly higher than 977 in 2017 and 952 in 2018. The number of lab-confirmed cases is estimated at 1,566. For 2019, the number of cases of acute gastroenteritis caused by Salmonella in the population is estimated at 25,971. The cost of illness associated with this equals €19 million (U.S. $22.4 million).

Infections with Salmonella Enteritidis were more often contracted abroad in 2019 than Typhimurium. The share of Salmonella Infantis infections contracted abroad decreased significantly from 2018 to 2019, while the total remained the same.

The proportion of Salmonella Typhimurium and monophasic Typhimurium was significantly lower than previous years. However, there was a higher proportion of Salmonella Enteritidis than in 2016/2017 when an outbreak related to Polish eggs caused more than 200 illnesses in the country. There is currently no clear explanation for this increase, according to experts.

A Salmonella Enteritidis outbreak of 39 cases was associated with eggs, with a link also to people sick in Norway and Germany. In the Netherlands it was not possible to find the source but the investigation in Germany led to a Dutch laying hen company. Another Salmonella Enteritidis cluster involving 34 cases was traced to eggs from Spain.

A Salmonella Enteritidis outbreak with 14 cases and one of Salmonella Typhimurium with 12 patients remained unsolved. Eleven cases in the Netherlands were part of an international outbreak involving six countries of Salmonella Muenchen. The incident subsided on its own and the source was not identified.

Three WGS-confirmed cases of Salmonella Virchow were identified in 2019 and six in 2020 linked to poultry from three slaughterhouses in the Netherlands and a batch imported from Brazil based on positive food samples from 2018 and 2019.

STEC signals
The number of STEC infection reports in 2019 was comparable to 2018 with 459 patients. The 35 STEC O157 and 59 non-O157 infection numbers were lower than previous years, because fewer isolates were submitted for typing. In total, 37 percent of STEC O157 patients were hospitalized compared to 25 percent of non-O157 STEC patients.

Hemolytic uremic syndrome (HUS) was reported for 22 patients, including 12 children aged 0 to 6 years old, three aged 9 to 16 and seven adults aged 21 to 81. Twice it was due to O157, four times because of O26 and O113 once. A woman with HUS (O typing unknown) died due to STEC infection.

For STEC non-O157, STEC O26 was found most frequently, followed at a distance by STEC O63 and STEC O103 and STEC O111. A total of 25 different O groups were found.

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