COLUMBUS, Ohio -- Four Ohio State University scientists are part of a multi-state $25 million effort to reduce the number of foodborne illnesses caused by viruses.
The five-year U.S. Department of Agriculture grant is the largest single food safety grant awarded by the USDA's National Institute of Food and Agriculture.
Under the leadership of North Carolina State University, the grant allows the formation of the Food Virology Collaborative involving more than a dozen universities as well as food and health organizations including the Centers for Disease Control and Prevention, the Food and Drug Administration, and Cincinnati Children's Hospital.
Tom Vilsack, U.S. Secretary of Agriculture, announced the grant Aug. 3 at the annual meeting of the International Association for Food Protection in Milwaukee. Lee-Ann Jaykus, professor in the Department of Food, Bioprocessing and Nutrition Sciences at NC State, is the lead investigator.
"We'll be involved in this project with some of the very best people in the country," said Richard Linton, who is one of the Ohio State scientists involved. Linton, currently at Purdue University, starts at Ohio State on Aug. 15 as professor and chair of the Department of Food Science and Technology.
The project focuses on human noroviruses, which cause more than 21 million cases of foodborne illness each year and are the second-leading cause of gastroenteritis in children under 5 years old. More than half of all foodborne disease outbreaks are due to noroviruses, and they are also the second-leading cause of hospitalizations due to foodborne illness.
Noroviruses spread from person to person, through contaminated food or water, or by touching contaminated surfaces. Molluscan shellfish such as oysters, clams and mussels, fresh produce, and foods that are extensively handled just prior to consumption are at greatest risk for contamination. Symptoms mimic those of salmonella food poisoning, including diarrhea, nausea, abdominal pain and fever.
"The illness is short-lived, maybe a couple of days, but it's not anything you want," Linton said. "And because it's so rampant, its economic impact is pretty strong when you account for time off work and going to the doctor.
"It's very easily transferred from person to person, and unlike other organisms, it's very hard to stop its spread once an outbreak begins," Linton said.
The project has six core objectives:
• Develop improved methods of studying human noroviruses and their role in foodborne illnesses.
• Develop and validate rapid and practical methods to detect human noroviruses.
• Collect and analyze data on viral foodborne illnesses -- including how they are transmitted -- and provide risk and cost analyses.
• Improve understanding of how human noroviruses behave in the food-safety chain in order to develop scientifically justifiable control measures.
• Develop online courses and curricula for food safety and health professionals and food-service workers, and provide information to fresh produce and shellfish producers and processors on the risks, management and control of foodborne viruses.
• Develop a public literature database, build virus research capabilities in state public health laboratories, and develop graduate-level curricula to educate master's and doctoral students trained in food virology.
As part of the project, Linton will use $500,000 of the grant to work with scientists at Rutgers University to better understand the routes of transmission of norovirus in retail and food-service settings.
"We think most of the illnesses associated with norovirus come from the last point of contact, such as in a food-service setting," Linton said. "Many times, all it takes is one outbreak and a restaurant operation can't recover -- they can't withstand the damage to their brand. We want to develop interventions to be able to control the organism and to minimize routes of transmission and develop training programs to help the food industry lessen the risk."
Also involved from Ohio State are Jianrong Li, assistant professor of food science and technology and environmental health sciences; Linda Saif, distinguished university professor in the Food Animal Health Research Program at Ohio State University's Ohio Agricultural Research and Development Center (OARDC); and Qiuhong Wang, a research scientist and adjunct assistant professor (Department of Veterinary Preventive Medicine) in Saif's lab.
For his part, Li has been granted $350,000 to work on several aspects of the project, including:
• Studying thermal (heat, steam and microwave) and non-thermal (high pressure, gamma irradiation and ultraviolet light) processes to determine how effective they are in inactivating the virus.
• Examining different ways to kill the virus, including damage to the capsid (outer layer) protein, the genetic material inside the virus, and interrupting the ability of the virus to bind to cell receptors. "If the virus can't bind to cells, it can't cause illness," Li said.
• Studying different strains of the virus to determine if treatments are effective against them. Noroviruses are classified into five genogroups and then further divided into genotypes, Li said. "To date, at least 33 norovirus genotypes have been identified. The human norovirus found in Ohio may be different from the one in Pennsylvania or the one in California. We hope to find a technology that will work on all of them."
• Working with a newly discovered surrogate virus, the monkey calicivirus, as a way to test the vulnerabilities in the human norovirus. "The human norovirus can't be grown in cell culture -- outside the human body -- so that's a real bottleneck in developing strategies to fight it," Li said. "Other scientists in this project are working on developing a way to grow the virus in cell culture, but until then we have to use surrogates to study the effectiveness of treatments against human norovirus." The human norovirus is in the same family as the monkey calicivirus, discovered at Tulane National Primate Research Center three years ago, Li said. The viruses have similar structures and biochemical properties, and they are genetically related to each other. In addition, the monkey calicivirus causes similar symptoms in primates (loose stools), and similarly binds to cells as the human norovirus, making it a strong surrogate, Li said.
Meanwhile, Saif's lab in Wooster is getting $500,000 for its part of the project. One portion of it involves Wang, who will study another type of calicivirus, called sapovirus. Porcine sapovirus was discovered in Saif's lab in 1980. It infects piglets in much the same way as norovirus infects humans; human strains cause diarrhea. Over the years, scientists in Saif's lab have developed novel approaches to grow sapovirus in cell culture, making it much easier to study.
Wang plans to develop a model comparing how sapovirus and human norovirus react to heat and disinfectants, including chemical treatments and UV light. Though just a small part of the project, Wang has already attracted the interest of Akron-based GOJO Industries, Inc., which makes hand sanitizers and other skin care products.
"They're very interested in these studies," Wang said. Her previous work has enabled the lab to grow sapovirus in high concentrations in the lab, which will allow a more precise measurement of the effectiveness of the different interventions.
Finally, Saif and other scientists in her lab will build on previous work using animal models to reproduce human norovirus and attempt to adapt the viruses to grow in culture.
"A few years ago, some of my graduate students were able to get large volume stool samples from people infected with human norovirus -- they aren't all that easy to come by," she said. "Within the last five years or so, we were able to take those human pathogens and infect germfree piglets and calves, inducing diarrhea and shedding -- giving us a steady supply of the human norovirus to study and enabling us to test vaccines or antivirals. This was the first time anyone has been able to replicate the human strain in an animal model."
Saif has uncovered evidence that, like in people, some germfree pigs and calves are more susceptible to human norovirus than others, depending on genetic makeup and related blood type factors. She will use the animal models to study this more closely. And, she plans to use animal cells in an attempt to grow the human norovirus in culture.
"That's the holy grail of scientists working on noroviruses," she said. "So many have tried, and so many have failed. But it's so important that scientists have published their failures so others can learn from them. It's not often that a scientist will publish work that has failed. But with our animal models, we feel we're in a unique position to advance the science in this field. That's one of the advantages of OARDC -- these animals are expensive to maintain, but they're key to our work."
The team members are all part of Ohio State's College of Food, Agricultural, and Environmental Sciences.