Foodborne outbreaks decrease in Denmark
The number of human infections with Campylobacter (3,782 cases) and Salmonella (1,122 cases) remained at the same level in 2014 as the last two years.
Compared to 2013, fewer foodborne outbreaks were registered in 2014 (60 compared with 74), with 2,209 cases registered of which 295 were confirmed in the laboratory.
Listeria monocytogenes cases increased 84% - mainly due to one outbreak in “rullepølse” - a Danish cold cut ready-to-eat speciality made from pork.
The number of persons affected by foodborne outbreaks was 2,209 with the largest outbreak involving 430 caused by Norovirus (NoV) in a canteen serving a buffet meal.
Source of illness appeared to be one of the kitchen staff who had attended a sick child at home with the same symptoms.
The report was compiled by the National Food Institute, Technical University of Denmark, the Danish Veterinary and Food Administration, and Statens Serum Institut.
Salmonella surveillance
Although the number of human Salmonella cases was similar to 2013, some changes occurred.
The number of infections with S. Enteritidis reduced by 22.5% compared to 2013, where a large travel-related outbreak occurred, despite three outbreaks in 2014, including the first from domestic eggs since 2009.
Human S. Typhimurium cases (incl. monophasic S. 1,4,[5],12:i:-) increased by 26.7% in 2014 compared to 2013, primarily due to an 81.1% increase in monophasic S. 1,4,[5],12:i:- infections related to five outbreaks. In four of these the source was domestic pork or beef.
An outbreak of S. Agona in 2013 and 2014 had an uncommon age and gender distribution. Investigations concluded whey powder was a possible outbreak source, but final identification was not possible.
Isolates of S. Typhimurium and S. Enteritidis have, since 2013, been subtyped using multiple-locus variable-number tandem repeat analysis (MLVA).
Among the cases with known travel history, 46% were infected abroad with the majority of cases travelling to Thailand (17.5%), Turkey (15.4%), and Spain (6.4%).
Listeria and VTEC findings
Listeria monocytogenes cases increased 84% including four outbreaks, one of listeriosis in “rullepølse” with 41 cases reported and a mortality of 41.4%. Seventeen cases died within 30 days from the laboratory sample date.
In 2014, Whole Genome Sequencing (WGS) was introduced as the routine typing of Listeria isolates as was parallel on-time testing of human and food isolates with WGS and Multi-Locus sequence Typing (MLST).
VTEC and Yersinia enterocolitica increased by 33.3% and 25.2%, respectively.
In 2014, a total of 280 episodes of verocytotoxin- producing E.coli (VTEC) were notified. VTEC isolates were obtained from 229 episodes, of which 37 (16%) were caused by O157.
Three outbreaks were registered with VTEC. On average, less than one outbreak per year has been registered in the last five years, and the last outbreak was October 2012.
Increased awareness and improved diagnostic methods play a role in the increasing number of VTEC cases.
For both pathogens, outbreaks contributed to the increase, but only for one small VTEC outbreak the source of infection was identified (beef of Danish origin).
