Leading Causes of Viral Foodborne Illness: Norovirus, Hepatitis A, E


A joint meeting of WHO and FAO offered this assessment of these viruses that millions of people encounter.

From a collaborative meeting held last month between the World Health Organization (WHO) and the Food and Agriculture Organization of the United Nations (FAO), they issued a summary report declaring the 3 leading causes of foodborne illnesses were human norovirus, then hepatitis A and hepatitis E. 1

The 2 types of hepatitis were ranked equally but higher compared to norovirus in terms of clinical severity, according to the expert committee that did the assessment.

The Joint FAO/WHO Expert Meeting on Microbiological Risk Assessment (JEMRA) on microbiological risk assessment of viruses in foods was held in Rome, Italy September 18-22, in response to the request by the Codex Committee on Food Hygiene (CCFH) at its 53rd session in 2022. The summary report was released earlier this month.

The expert committee carried out 4 elements to measure the rankings, including the following:

1) reviewed the literature and available surveillance databases, and participated in an expert knowledge elicitation, which ranked foodborne viruses according to frequency and severity;

2) ranked the relevant food commodities of highest public health concern;

3) discussed methods for virus testing performed for outbreak investigation and product testing as part of surveillance and monitoring strategies; and

4) reviewed current and potential indicators for viral contamination.

The committee noted that water intended for drinking was not within the scope of their work and that water relevant to virus transmission was considered only for water used in food production, processing, and preparation; used as an ingredient, and as a vehicle for food contamination; where water is not the final product that is consumed.

What You Should Know

The meeting identified the three leading causes of foodborne illnesses. These are human norovirus, hepatitis A, and hepatitis E. While norovirus is the most common, hepatitis A and hepatitis E are considered equally significant but rank higher in terms of clinical severity.

The expert committee utilized a comprehensive approach to rank these viruses and relevant food commodities. They reviewed literature, participated in expert knowledge elicitation, discussed virus testing methods, and reviewed potential indicators for viral contamination. Their rankings were based on frequency and severity.

The meeting highlighted the global significance of foodborne illnesses. In the United States alone, foodborne illnesses are a frequent occurrence, with millions of people affected each year.

The Enormity of Foodborne Illness and When to Seek Medical Care

Foodborne illness is a very frequent occurrence in the United States. The Centers for Disease Control and Prevention (CDC) estimates 1 in 6 Americans (or 48 million people) get sick, 128,000 are hospitalized, and 3,000 die from foodborne diseases annually in the US.2

In terms of symptoms, foodborne illness can create gastrointestinal infections with symptoms including diarrhea and/or vomiting, which can last 1 to 7 days. Other symptoms might include abdominal cramps, nausea, fever, joint/back aches, and fatigue. For any of these leading causes of foodborne illnesses, there are no current FDA approved therapies.2

CDC recommends calling your health care provider if you have severe symptoms such as:

  • Diarrhea and a fever higher than 102°F
  • Diarrhea for more than three days that is not improving
  • Bloody diarrhea
  • So much vomiting that you cannot keep liquids down, which can lead to dehydration
  • Dehydration, which causes symptoms such as dry mouth and throat, feeling dizzy when standing up, and not urinating much

Committee Recommendations

The US has federal agencies trying to prevent foodborne illness as well as protocols in place to let the public know about outbreaks. In low-to-middle income countries, these protocols might not be in place to prevent further outbreaks from happening.

“Member countries consider capacity building to support training and adoption of these methods for detecting viruses in foods and the environment. This approach has the potential to enhance knowledge on food attribution, support risk analysis, and reduce the burden of viral foodborne disease worldwide. Appropriate global actions will help alleviate the anticipated increase in public health risk from viral foodborne illness arising from population growth, the climate crisis, and globalization of food supply chains,” the report authors wrote.

The full report will be made available at a later date.


1.Joint FAO/WHO Expert Meeting on microbiological risk assessment of viruses in foods - Part 1: food attribution, analytical methods and indicators. WHO. September 18, 2023. Accessed October 24, 2023. https://www.fao.org/3/cc8193en/cc8193en.pdf

2.Fast Facts About Food Poisoning. CDC. Last reviewed March 24, 2023. Accessed October 24, 2023. https://www.cdc.gov/foodsafety/food-poisoning.html

Related Videos
© 2024 MJH Life Sciences

All rights reserved.