Public health officials in an Australian state have warned people about a rise in Listeria infections.

New South Wales (NSW) Health is reminding people who are immunocompromised, pregnant, or aged over 65 years old to avoid foods that can cause listeriosis.

There are typically 20 to 30 cases of listeriosis reported each year in NSW. 

At the end of May 2023, 17 listeriosis notifications had been recorded, which was above the five-year average of 10 cases for the same period. No common foods had been identified and whole genome sequencing has not detected any clustering.

Keira Glasgow, director of NSW Health’s One Health branch, said the advice follows a rise in reported cases and the number of people treated in hospitals for their illnesses.

“Already in 2023, we’ve recorded 25 cases of listeriosis among NSW residents, which is more than we usually expect to see in a whole year,” she said.

“There are a range of foods that present very real risks to people who are older, pregnant or have underlying health conditions such as cancer, diabetes, heart, liver, or kidney disease, or who are on medications such as corticosteroids which impact immune systems.”

People at increased risk of Listeria infections are advised to avoid certain foods, to take care not to contaminate fruit when cutting it and not to store cut fruit and vegetables that are eaten raw, as Listeria survives refrigeration.

Risky foods include cold delicatessen meats, smoked seafood, rockmelon (cantaloupe), pâté or meat spreads, unpasteurized milk products, sprouted seeds, soft cheeses and soft serve ice cream.

Infections up in the Northern Territory
Health officials in another state also issued a recent warning following a rise in cases of rotavirus, norovirus and other causes of gastroenteritis. 

Northern Territory (NT) Health has reported 112 cases of rotavirus in 2023. This is an increase compared to the average number recorded up to August 31 in the past five years.

Gastroenteritis is spread by eating food or drinking water that has been contaminated by infected animals or people. It can also be acquired by handling contaminated objects or surfaces and then touching your lips or mouth or preparing or eating food without washing hands.

Norovirus is another cause and may have been responsible for several outbreaks in the region in the past month.

NT Health has reported 168 cases of cryptosporidiosis in 2023. This is double the average number of cases recorded over the past five years.

Illness can be prevented through simple measures in food preparation and hygiene including washing hands regularly with soap and warm water, especially before and after preparing food and after going to the toilet; ensuring meat, fish and poultry are cooked thoroughly; and ensuring cutting boards, knives and plates for raw food are kept separate from ready-to-eat-foods.

Anyone with diarrhea or vomiting is advised not to prepare or handle food for others and to stay home from work, school or childcare for at least 24 hours after the last episode of diarrhea or vomiting. This is 48 hours for healthcare workers or people who work in food preparation.