Warm oceans, unusual currents and strange weather patterns have coincided with an outbreak of disease that has forced the closure of South Australia’s Coffin Bay farms.
Health authorities have said they would now investigate whether climate change was a factor in the spread of Vibrio parahaemolyticus in oysters, which has been linked to 45 cases of gastroenteritis since September.
Undercooked shellfish and fish can carry Vibrio, which in turn can cause diarrhoea, vomiting, cramps, fever and headache. Raw oysters are often the cause of Vibrio infection.
Oyster production in Coffin Bay, SA, has been stopped while the most recent outbreak is investigated.
SA Oyster Growers Association executive officer Lynlee Lowe said the industry was deeply concerned about the cases and would work with a range of agencies to identify the cause.
“We are examining highly unusual environmental conditions, something which has not been seen before in SA, which have coincided with this outbreak,” she said.
“[There have been] strange weather patterns, unusual ocean currents, ocean water [temperatures] for this time of year.”
Asked whether it was likely to be climate change-related, Lowe said: “That’s something we’re looking into. We’ve got a project with the SA Research and Development Institute, looking at what environmental factors have affected this outbreak, and we’ll use that for future cases that might happen in SA, NSW and Tasmania.”
In recent years evidence has emerged that warmer oceans cause Vibrio outbreaks in oyster hatcheries. A team of researchers from a range of Australian universities is currently investigating Vibrio blooms as marine heatwaves become more frequent and more intense.
SA Health warned the related illness could be serious, particularly in people who are older, pregnant, or immunocompromised.
Nathan Rhodes, biosecurity executive director at SA’s primary industries and regions department, said it could be difficult to pinpoint the exact cause of an outbreak, and that inspection had shown the correct food safety practices were in place on the farms.
The Coffin Bay closures are likely to continue at least until next week.
