Most people enjoy Louisiana oysters, but bringing them to the table is not as easy as throwing a net out to sea.
Zhi-Qiang Deng, associate professor of civil and environmental engineering, conducts research to assist prevention of norovirus outbreaks among oyster harvesting locations.
“Most people think they’re unpredictable,” Deng said, but he said his research shows otherwise.
Last April, Deng, working with the Louisiana Department of Health and Hospitals and the National Aeronautics and Space Administration satellite data, successfully predicted an outbreak in Cameron Parish and was able to harvest areas several months before it occurred.
The Federal Drug Association’s National Shellfish Sanitation Program requires all states to test state growth waters for safety approval.
According to Deng’s website, NASA’s environmental data, along with regular bacteria sampling and analysis, is used to develop a system that focuses on predictions rather than reactions after an outbreak occurs.
Deng said outbreaks typically occur around the winter holidays and early January, but not always. Outbreaks are typically related to the consumption of raw oysters.
John Supan, assistant professor at the LSU AgCenter’s School of Renewable Natural Resources, said while norovirus is classically associated with oysters, people may also be exposed by eating raw vegetables like spinach.
Supan said oysters can be riskier to eat because people consume them raw and whole.
Supan said people infected with norovirus may experience flu-like symptoms such as nausea, vomiting, headaches and diarrhea.
The virus spreads across humans in congested areas, like hospitals or senior care housing, the same way a common cold does, Deng said.
Supan said these tests look for bacteria that occur in fecal material, which is another way norovirus may spread.
“Sick people with flu symptoms shouldn’t be out on the water,” Supan said. “And people should not discharge any sewage overboard.”
Supan said thoroughly cooking oysters helps reduce the risk.
“You’re not eating the gut of a shrimp, you’re just eating the tail,” Supan said.
Supan said consuming the gut of an animal is more dangerous than eating the regular flesh.
Deng said if contamination occurs during low-tide periods, the likelihood of an oyster becoming infected increases, as the infected water concentration is higher.
“Oysters work like pumps,” Deng said. “When they pump water through their tissues, it can spread.”
Supan said oysters pump approximately 8 liters of water per hour.
In the past, government agencies dealt with such problems as they occurred, rather than seeking methods to prevent them.
Deng said at least three cases must be reported to a government agency for an outbreak to be declared; if it is proved that the sick individuals ate raw oysters from the same area, the area will be closed, and the oysters will be recalled.
“But they may have already been sold in different states,” Deng said. “The cost can be very high, up to millions of dollars.”
Supan said outbreaks can have negative economic consequences, particularly in the parishes in which they occur because individuals who work as harvesters cannot go to work.