Urgent inquiry system to detect multi-country outbreaks evaluated
The Epidemic Intelligence Information System for food and waterborne diseases (EPIS-FWD) is a restricted access online platform launched in 2010 and helps exchange information between countries.
During 2008 to 2013, 215 outbreak alerts, or ‘urgent inquiries’ (UI), for food- and waterborne diseases were launched in Europe, the majority (63%) being related to salmonellosis.
Researchers said laboratories commonly test for and report this pathogen and serotyping and molecular typing can be effective in detecting case clusters.
The system is dependent on capacity and willingness of participating countries to launch and reply.
“A total of 10 EU/EEA countries did not launch any UI during the study period,” said the researchers.
“Considering the difference in number and rate of UI launched by participating countries, the threshold to launch UI appears to be extremely variable, with the countries in northern and western Europe having the lowest threshold for posting an UI.
“As it was not possible to define any criteria that identify which events reported as UI would become multi-country outbreaks, guidelines for posting an UI should not be restrictive and participating countries should be encouraged to post an UI as soon as they detect any unusual FWD event.”
The UI allowed early detection of multi-country outbreaks, facilitated identification of suspected vehicles and contributed to timely implementation of control measures, said the researchers.
Vegetables top category
For 110 (51%) UI, a potential food vehicle of infection was identified, with vegetables being the most reported category (31%).
This was followed by pork (14), beef (12), eggs (7), cereal products (7) and fruit (7).
A total of 28% of the outbreaks involved at least two countries.
Of 60 multi-country urgent inquiries, 50 involved between two and four countries.
In 10 UI, at least five countries were involved per urgent inquiry, including an outbreak of S. Stanley infections in the EU in 2012 and hepatitis A associated with travel to Egypt in 2013.
Multi-country outbreaks were primarily due to distribution of a contaminated product to multiple countries (35 outbreaks) and to travel of people to a common country/place of infection (19 outbreaks), according to the study.
For 76 UI (35%), the trigger for posting was less than 10 human cases and six were launched after identification of a contaminated food product, without any human cases reported.
STEC and Listeria were the number two and three pathogens reported, respectively.
“UI may be particularly valuable for Listeria outbreaks because the disease does not have a high attack rate and listeriosis outbreaks are frequently due to consumption of manufactured products potentially distributed internationally (e.g. cheese, fish) rather than mishandling of food in restaurants or households as for Salmonella.”
Campylobacteriosis was the most commonly reported foodborne disease in the EU/EEA during the study period but no UI were launched.
“Campylobacter samples are not subtyped routinely and no discriminative and reliable subtyping system exists so dispersed, continuous outbreaks are therefore unlikely to be detected,” said the researchers.
Up and down trends
Between January 2008 and December 2013, 215 UI were issued by participating countries.
The number changed with 32 in 2008, 27 in 2009, 33 in 2010, 49 in 2011, 32 in 2012 and 42 in 2013.
The moving average highlights some seasonality in the northern hemisphere, with peaks during spring and summer.
The majority of the UI were posted by the UK (27), France (21) and Denmark (20). Among the participating non-EU/EEA countries, the US posted the most (18).
A total of 15 diseases and intoxication syndromes were reported. Salmonellosis and STEC infection represented 63% and 15%, respectively.
A total of 50 Salmonella serotypes with the two most common being S. Typhimurium (34), including its monophasic variants 1,4,[5],12:i:-, and S. Enteritidis (22).
Seven STEC serogroups were reported, of which serogroup O157 was the most predominant (20/32).
Others included O26, O27, O104, O121, O145 and O177.
For 110 UI, a food vehicle of infection was either suspected or confirmed, through descriptive and/or analytical epidemiological studies.
For 93 the vehicle or origin of infection remained unknown. For seven, infection was due to direct contact with animals; for four, it was water; and for one, it was a laboratory-acquired infection.
Source: Eurosurveillance, Volume 20, Issue 25, 25 June 2015
“Event-based surveillance of food and waterborne diseases in Europe: Urgent inquiries (outbreak alerts) during 2008 to 2013”
Authors: C M Gossner, B de Jong, C J Hoebe, D Coulombier, European Food and Waterborne Diseases Study Group
