No 12 - 2011

Zoonotic and intestinal infections 2010

Zoonoses are diseases transferred from animals to humans. Zoonotic intestinal infections arise after ingestion of contaminated foodstuffs or water, or after contact with infected animals or humans.

Bacterial enteropathogens are monitored through the laboratory surveillance system. Furthermore, VTEC infections and cases of haemolytic uraemic syndrome (HUS) are clinically notifiable on form 1515, as is food-borne infection on suspicion of a particular meal or foodstuff.

Overall development

The number of salmonella cases decreased to 1,600 (29 per 100.000) from 2,129 cases in 2009, Figure 1.

S. Typhimurium was the most frequent serotype, Table 1. In 2010 the number of cases of this type decreased by 31 % compared with 2009 when several major outbreaks occurred.

S. Enteritidis decreased by 35 % in comparison with 2009, while the group of other serotypes, comprising a total of 691 cases, decreased by 9 %.

This last group comprised 110 different serotypes.

In 2010, a total of 4,035 (73 per 100.000) Campylobacter jejuni/coli infections were reported, equivalent to a 20 % increase relative to the preceding year, Figure 1.

A total of 192 Yersinia enterocolitica cases (3.5 per 100.000) were recorded, 19 % down from 2009, Figure 1. 

A total of 185 cases of verocytotoxin-producing E. coli (VTEC) were observed (3.3 per 100.000), corresponding to a 10 % increase from the previous year. Isolates were available for 171 VTEC cases and among these, the two most frequently occurring serogroups were O157 and O103, both with 25 (15 %) cases.

A total of 185 VTEC cases were notified, including seven which could not be identified in the laboratory surveillance system.

Three HUS cases were notified, all of which were confirmed VTEC cases. The age-specific incidence is listed in Table 2.

Further information about the number of bacterial intestinal infections is presented at "Tal og grafer".

Infections acquired abroad

In 2010, as previously, the SSI collected travelling information by phone interviews from all salmonella patients and patients with Campylobacter infections residing in the former counties of North Jutland, Aarhus and Roskilde.

The patients were asked about the date of disease onset and if they had travelled abroad within a seven-day period prior to disease onset.

Information was obtained from a total of 78 % of the salmonella and 74 % of the campylobacter cases.

Among the responding patients, 36 % of campylobacter cases were acquired abroad, while the corresponding figures were 76 % for S. Enteritidis, 15 % for S. Typhimurium and 54 % for the remaining serotypes.

The final figure comprises considerable variation in terms of serotypes.

For Salmonella, the primary country of infection was presumably Egypt, followed by Thailand and Turkey.

For Campylobacter, the primary country of infection was Turkey followed by Thailand and Spain.

Commentary

Campylobacter remains the most frequent cause of bacterial intestinal infection in Denmark, and the number of infections increased in 2010 after having decreased for two consecutive years.

This increase has no obvious cause. Poultry is regarded the primary source of infection. Approximately one third of the patients are infected abroad.

The number of salmonella infections continued to decrease, which - among others - is the result of relatively fewer cases in the outbreaks registered in 2010.

Notably, the number of S. Enteritidis infections - which is mainly transferred by consumption eggs - was the lowest registered in the past 25 years.

Furthermore, it is estimated that approx. 3/4 of S. Enteritidis infections were acquired abroad which makes this previously very frequent serotype rare as a Danish food-borne infection.

The number of S. Typhimurium cases was somewhat higher, among other reasons due to a prolonged outbreak counting 172 cases, which was traced back to a swine slaughterhouse, EPI-NEWS 42-43/10.

(S. Ethelberg, K. Mølbak, Dept. of Epidemiology, K.E.P. Olsen, F. Scheutz E. M. Nielsen, DBMP)

World TB Day 2011

The 24th of March 2011 is World TB Day.

The European Centre for Disease Prevention and Control (ECDC) marks the day by focusing on tuberculosis (TB) in children using the slogan "Tackling tuberculosis in children: Towards a TB-free generation".

For more information, please see www.ecdc.europa.eu.

More than 40,000 children in the EU have been diagnosed with TB in the past decade. TB in children comprises 4.2 % of all TB cases in the EU and in some areas of the EU, TB in children is increasing.

TB in children is particularly challenging to diagnose and among all the cases of child TB observed in the 2000-2009 period, only 19% were verified by culture.

A WHO/ECDC panel of experts stresses the need for new tools for the diagnosis of TB in children and for child-friendly TB treatment regimens and TB medication formulations.

Research in these focus areas should be prioritized as a reduction of TB in children will benefit the overall fight against TB.

(B. Søborg, Dept. of Epidemiology)

Individually notifiable diseases and selected laboratory diagnosed infections (pdf) 

23 March 2011