Food Virology Collaborative: NoroCORE Tackles Foodborne Viruses
By Catharine L. Gensel, Otto D. Simmons, Ph.D., and Lee-Ann Jaykus, Ph.D.
When one thinks of foodborne pathogens, Salmonella, Escherichia coli and Listeria monocytogenes are a few that come immediately to mind. But viruses are the leading cause of foodborne illness in the U.S., surpassing the number of cases attributed to bacteria. The notable culprits, noroviruses, have been called the “perfect pathogen,” reflecting many traits that make them particularly successful. Specifically, norovirus is highly infectious, has a low infectious dose, is rapidly spread by a variety of routes, is environmentally stable, is resistant to many sanitizers and disinfectants, is constantly evolving and evokes a limited immune response (i.e., short-term immunity).
Although other enteric viruses (e.g., hepatitis A virus) contribute to foodborne illness, noroviruses are by far the most prevalent. Noroviruses are transmitted by ingesting the pathogen through contaminated food or water, or by person-to-person contact. Norovirus has been attributed to foodborne outbreaks most often associated with the foodservice industry, food handlers and preparatory settings, fresh produce and molluscan shellfish.[2, 3]
Classic symptoms of norovirus disease are nausea, vomiting, diarrhea and abdominal pain with occasional headache and low-grade fever. Vomiting is considered the hallmark symptom. The symptoms usually last no more than 2 or 3 days. Rehydration therapy is the best treatment to date, but severe illness or hospitalization is relatively uncommon except in the elderly. However, due to the sheer magnitude of cases, noroviruses rank second in causes of foodborne disease hospitalization. Death is rare.
There have been many high-profile norovirus outbreaks in the last decade. Perhaps first widely publicized as the “cruise ship virus,” noroviruses are now known to cause outbreaks in many places where people are kept in tight quarters: long-term-care facilities, schools and dormitories, military establishments, even hotels. Relative to foodborne disease, there are many notable outbreaks. For instance, in 2012, thousands of schoolchildren in Germany were sickened with norovirus-contaminated imported strawberries. Food handler hygiene is particularly important. In fact, as this was written, over 1,000 Japanese schoolchildren were infected by bread that appears to have been contaminated by food handlers who were shedding norovirus in their feces but were perhaps asymptomatic. Besides feces, noroviruses are released during vomiting, and outbreaks have resulted from foods that were contaminated because individuals vomited in preparation kitchens.
Taking a Closer Look
The U.S. Department of Agriculture-National Institute of Food and Agriculture (USDA-NIFA) Food Virology Collaborative (NoroCORE, Norovirus Collaborative for Outreach Research and Education) formed in 2011. NoroCORE is a 5-year, $25 million Coordinated Agricultural Project funded by USDA-NIFA. As an “integrated” project, it includes efforts in all three of the traditional land-grant missions: research, education and extension/outreach. The purpose of the latter is to extend basic and applied scientific findings to a broader audience so that NoroCORE results translate to real-work processes and actions that reduce the burden of virus-associated foodborne disease. The project is highly collaborative and interdisciplinary. All these are features of what is now referred to as the “new biology” approach to science, that is, projects that seek to provide real-world solutions to complex and relevant societal problems, including improvements in human health.
The long-term goal of NoroCORE is to reduce the burden of foodborne disease associated with viruses, particularly noroviruses. This is being addressed using a multidisciplinary team working in an integrated manner to develop improved tools, skills and capacities to understand and control foodborne virus disease risks. Based on its primary objectives, the project’s efforts fall into six “cores” that fit into the following target areas: molecular virology, detection, epidemiology and risk analysis, prevention & control (these are the research cores), extension & outreach and capacity building. Each core has lead investigators specialized in that particular area and numerous collaborating partners across multiple institutions. A snapshot of the purpose of each core is provided below, and the corresponding text box on page 72 provides greater detail on each core’s specific activities.
Who Is Involved?
NoroCORE is based at North Carolina State University (NCSU) and is led by Lee-Ann Jaykus, Ph.D. In addition to NCSU, which serves as the lead institution, the team consists of research groups from 21 partner institutions (see Table 1), with stakeholders across industry, government and academia. Many of these institutions have multiple teams that participate on the project. Additional institutions have become involved in the collaborative via receipt of competitive mini-grant awards provided each year to qualified applicants.
As part of extension and outreach, the collaborative has extensive efforts in place to engage relevant stakeholders, with each stakeholder group engaged in the manner most appropriate to that sector. With this in mind, the NoroCORE group has convened a shellfish advisory panel comprising key members from the Interstate Shellfish Sanitation Conference, representing the federal government, individual states and key researchers. To integrate virus-related information into national efforts targeting the fresh produce industry, the NoroCORE group is working closely with the Produce Safety Alliance by providing suitable information that can be integrated into the national Good Agricultural Practices program the alliance is developing. Extensive dialogues with the foodservice and retail/grocery sector are ongoing to identify the best activities to further engage this sector. Right now, the NoroCORE team is focusing on better training for food handlers and development of more standardized protocols for cleanup after vomiting events, and also sanitation of locations that might serve as reservoirs for norovirus contamination, such as restrooms and children’s play areas. Those companies involved in development, manufacture and marketing of sanitizers and disinfectants serve advisory roles and also work with NoroCORE team members in research collaborations. Individual companies manufacturing detection kits, or providing testing services to the food industry, have engaged NoroCORE members for consultation. The collaborative is also working on education and outreach materials targeting consumers and the public health community at large. NoroCORE will soon be launching several social media campaigns.
Program Activities & Successes to Date
NoroCORE researchers have been busy addressing the many needs associated with understanding and controlling foodborne viruses in the food chain. Below are a few successes in the first two project years.
• Comprehensive validation of the utility of various cultivable surrogate viruses for examining the environmental behavior of human noroviruses, which are noncultivable
• Development of more broadly reactive ligands that can be used to facilitate human norovirus detection in clinical and especially foods and environmental samples
• Development of a microarray-based method for genotyping the vast array of human norovirus strains
• Up-to-date estimates of the economic burden of human norovirus disease in association with the retail food sector
• Up-to-date estimates of the burden of epidemic human norovirus disease, including attribution to specific foods[5–7]
• Characterization of thermal resistance of human noroviruses
• Identification of novel methods to inactivate human noroviruses on surfaces and in foods. Particularly promising approaches include the combined use of levulinic acid and surfactants for produce washing; copper for surface inactivation; and aerosolized hydrogen peroxide room disinfection
• Completion of surveys to characterize the base line knowledge of consumers and public health professionals regarding the importance of enteric viruses to foodborne disease to guide development of future training materials
The program launched Norocore.com, a fully functional website, which posts continuous updates and important information about NoroCORE, its objectives and its partners. The website includes frequent blog posts as norovirus outbreaks emerge. There are also efforts for outreach via social media—particularly LinkedIn (company page and group), Facebook (facebook.com/norocore) and Twitter (@NoroCORE).
Stakeholder meetings were held at the annual meeting of the International Association for Food Protection (IAFP) in 2012, including a stakeholder needs assessment. A full collaborative meeting was held in November 2012, which consisted of presentations by researchers and stakeholders and a poster session by investigators, stakeholders, staff and students. At IAFP 2013, NoroCORE unveiled a booth on the exhibit floor and sponsored a research symposium. These meetings provided opportunities to visit and network with collaborators and stakeholders, and to raise awareness of the NoroCORE program. Another collaborative meeting was held in November 2013, providing team members with the opportunity to update their colleagues on research progress and plan future steps for the activities of each core. The next full collaborative meeting, which brings together stakeholders, students and team members, is scheduled for November 2014.
Another success of the program relates to strengthening the skills, competencies and abilities of food safety professionals and others in the food industry to recognize the risks of viral foodborne illness and develop the interventions needed to reduce outbreak and illness events. Some of the developments NoroCORE has made in this area include:
• Development of the Food Virology Literature Database
This online literature database, dedicated solely to food virology and accessible via the NoroCORE website (or norocorelit.com), includes over 2,700 articles from 1992 to the present, is updated frequently and has full articles available to collaborating team members and abstracts available to nonmembers and the public (due to copyright restrictions).
• Reagent/Protocol Exchange and Training
The Reagent Exchange is a formalized/centralized means by which to share reagents and methods among collaborating institutions. Less formalized training and information exchanges regularly occur, with teams sharing data, research information, models and expertise with other collaborative members. Examples include training and collaboration between the Centers for Disease Control and Prevention and Clemson University, and between NCSU and Louisiana State University. Team members at the University of Georgia have created an OpenWetWare wiki page online to further foster the sharing of technical expertise.
• The NoroCORE Food Virology Graduate Curriculum
Currently in development, the curriculum will eventually be in distance-education format, which will allow comprehensive training of future food safety professionals about the role of viruses in the food chain and viral foodborne disease in relationship to the burden of food-associated disease.
In addition to stakeholder engagement efforts, the collaborative has also produced specific outreach materials. One-page infosheets about noroviruses are available for specific industries. For example, info sheets exist for recreational boaters and marina managers that target both vomiting overboard and boat waste dumping, and for berry industry farm managers and harvesters/pickers that target virus contamination risks in berries. The berry sheets are linked to and promoted by the Produce Safety Alliance. Extension team members are working on developing additional info sheets and infographics. These resources are available at the NoroCORE website.
Where Do We Go from Here?
The NoroCORE project is beginning its third of 5 years. Significant progress has been made to date, with most of the groundwork set and critical mass met for even greater strides over the coming years. Team members are strongly committed to working collaboratively, and this collaboration is fundamental to the new biology concept that serves as the foundation for this project. NoroCORE is showing that substantial strides can be made in solving large, real-world challenges through multidisciplinary collaboration in which participating scientists respect the strengths that each brings to the table. In this think-tank environment, scientists working in complementary areas can come together to pool their backgrounds and knowledge and can symbiotically push the group to be better than any one individual working on his/her own. As the project continues to grow, Dr. Jaykus and other team members actively engage government and industry groups to have a better understanding of the larger issues and what the current needs are for reducing viral foodborne illnesses. Flexibility built into the project allows this feedback to help focus the research that the group tackles.
The heart of the project is to take the knowledge gained from research and, based on stakeholder and consumer needs, translate this information into sound, practical solutions that will lead to lasting positive impacts on public health. NoroCORE’s dedication to capacity building and extension/outreach, which includes the education of current and future members of the field (and all of its related disciplines), ensures that critical knowledge and tools will be carried forward. Through the research momentum generated thus far, and the capacity building and outreach efforts in progress, the impacts of this project should continue to cascade through the field long after the funding period ends. It is our hope that NoroCORE will prove to be a model for future efforts to tackle society’s other real-life, big-picture challenges.
Catharine L. Gensel obtained a B.Sc. in zoology with a minor in microbiology and a B.A. in Spanish language & literature at NCSU. She is currently the administrator & communications director for NoroCORE at NCSU.
Otto D. Simmons, Ph.D., maintains joint appointments in the departments of biological and agricultural engineering and food, bioprocessing and nutrition sciences at NCSU and serves as an adjunct assistant professor in the School of Environmental Sciences and Engineering at The University of North Carolina at Chapel Hill.
Lee-Ann Jaykus, Ph.D., is William Neal Reynolds Distinguished Professor in the department of food, bioprocessing and nutrition sciences at NCSU. She received a Ph.D. in environmental sciences and engineering from the School of Public Health at the University of North Carolina in Chapel Hill. Her current research efforts are varied and focus on food virology, development of molecular methods for foodborne pathogen detection, application of quantitative risk assessment in food safety and understanding the ecology of pathogens in foods.
Opening image courtesy of X-ray crystallographic structure of the Norwalk virus capsid. Prasad, B.V. et al. 1999. Science 286: 287–290.
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