Norovirus tops the expert ranking of foodborne viruses

Experts named norovirus the leading cause of viral foodborne illness, followed by hepatitis A and hepatitis E.

Hepatitis A and E viruses were ranked equally but higher than norovirus in terms of clinical burden by scientists at a recent meeting organized by the World Health Organization (WHO) and the Food and Agriculture Organization of the United Nations (FAO).

In September, the FAO/WHO Joint Expert Meeting on Microbiological Risk Assessment (JEMRA) for viruses in food was held in Rome, Italy, in response to a request from the 2022 Codex Committee on Food Hygiene.

It focuses on food distribution, analytical methods and indicators. A summary of the findings has been published, with the full report available later.

The scientists reviewed the literature on foodborne viruses published since JEMRA’s 2008 report on the topic and information provided in response to a call for data.

Combinations of viruses and foods
Foodborne viruses were ranked by frequency and severity and by the type of food associated with the greatest public health concern.

Virus-commodity pairs associated with the greatest global public health burden include prepared food, frozen berries, and shellfish for norovirus. For hepatitis A, it was the same foods, but in a different order, with shellfish first and prepared foods third. For hepatitis E, pork ranks first, followed by game. However, the scientists said there were significant regional differences.

There was a lack of data to rank foods contaminated with astrovirus, sapovirus, enterovirus, intestinal adenovirus and rotavirus. The scientists said countries should step up research into foodborne illnesses and foods for these viruses.

Annually, norovirus is estimated to cause 125 million cases of foodborne illness and 35,000 deaths worldwide.

Hepatitis A virus is estimated to cause 14 million cases and 28,000 deaths annually and is a notifiable disease in some countries. For hepatitis E, no global estimate of food-attributable cases exists.

Experts also discussed virus testing methods in outbreak investigations and product testing as part of surveillance and monitoring strategies.

International Organization for Standardization (ISO) methods are widely used for the detection of norovirus and hepatitis A viruses in various commodities. Methods for the detection of hepatitis E virus in meat products are under development.

Current standardized methods are based on detection of viral nucleic acid, which does not necessarily indicate infectivity. The methods may be limited by factors such as food complexity and low levels of contamination. Research into indicators of viral infection is also needed.

The experts recommended that countries consider building capacity to support training and adoption of methods for detecting viruses in food and the environment.

“This approach has the potential to improve knowledge of food attribution, aid risk analysis, and reduce the burden of viral foodborne illness worldwide,” they said.

IAEA and FAO programme
Meanwhile, the International Atomic Energy Agency (IAEA) and FAO have created a new initiative.

Atoms4Food will support countries to use nuclear techniques to increase agricultural productivity, reduce food loss, ensure food safety, improve nutrition and adapt to the challenges of climate change.

Nuclear techniques can be used in a variety of ways as part of food security. Irradiation can play a role in keeping food safe from pathogens and increasing shelf life.

Through the initiative, the IAEA and FAO will assist seven areas, including the Food Safety and Control Service, to carry out individual assessments of a country’s laboratory capabilities and capacity to monitor food hazards.

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