Virginia’s Department of Health is using wastewater surveillance testing devised during the COVID pandemic to zero in on how a rare bacteria called Salmonella Telekebir infected parts of the Little Wicomico River.
Some of the infected oysters were grown and harvested by the Little Wicomico Oyster Company in Northumberland County.
Initial tests ruled out handling issues at the company’s facility and traced it to the water. On Friday, another round of tests ruled out human waste in the water as a potential source. That was a relief, as rural septic systems are common for homeowners here. The river is actually a small, nine-mile, estuary just south of the Potomac River along the Chesapeake Bay.
"So, this is a new thing for us to be dealing with at VDH with the Salmonella Telekebir," says Lance Gregory, director of the VDH Environmental Health Services. "FDA and CDC are our partners in this outbreak investigation. And so, we're still trying to learn how this salmonella got into the environment and then how it might be moved within the environment."
Oysters are filter feeders taking up what’s in the water. Salmonella Telekebir is among thousands of different types of the bacteria linked to the feces of animals.
"Maybe animals raised for food, things like pigs, cows, chickens. It can also be animals that we keep as pets, so things like lizards and turtles," Gregory says. "And the feces of those animals, if they have salmonella, can then contaminate food. And then people can get sick from eating the food that's been contaminated."
And climate change, like more intense rainstorms or drought, can boost the bacteria.
"More rain can bring more runoff into the river," according to Gregory. "So, more runoff can bring in more bacteria from the surface. And we do see with our routine monitoring, there's usually higher bacteria counts for two or three days after a rainstorm. And on the other side of that, with drought that can lead to less flushing and warmer temperatures in shallow coasts. So that doesn't necessarily introduce bacteria, but it could provide growth opportunities for bacteria."
As testing continues, Virginia’s oyster industry is concerned for sales as misinformation spreads during their biggest holidays – Thanksgiving and Christmas. A.J. Erskine works with the oyster industry and is a Virginia Marine Resources Commissioner.
"Even though it is specific and isolated to that growing area and one Virginia dealer, the rest of the shellfish industry in Virginia are getting phone calls from customers that are saying they're questioning the safety of Virginia oysters in general. Even on the national level this is not very good press for people that consume shellfish when they say 'Gosh I don't want to eat shellfish because I hear now it has salmonella.' They don't equate it to only a certain growing area and one dealer it's 'Hey we hear that Virginia's oysters have salmonella. Don't buy them.' And then on the national level 'Hey salmonella is in oysters so don't eat oysters.' So it has a lot of wide-ranging impacts," Erskine says.
"This is very isolated and we have 90 growing areas in the state of Virginia this is one growing area so there are many other growing areas that are open to harvest and processing and are safe to eat."
The Little Wicomico River will remain closed until waters test negative for salmonella.