What is the issue?
There is a national outbreak of listeriosis which has been linked to rockmelon (cantaloupe) from New South Wales. The Department has identified one Victorian as linked to the national outbreak, and further cases are under investigation.
Outbreaks of listeria have been linked to rockmelon consumption in the past, and risk may arise from consumption regardless of how the rockmelon is served, including in fruit salads.
Who is at risk?
People who are at an increased risk of listeriosis include those who have immunocompromising illnesses, the elderly, pregnant women and their foetuses, newborn babies or people on immunosuppressive drugs.
Symptoms and transmission
The main route of transmission is through ingestion of contaminated food. Other routes of transmission include from mother to foetus via the placenta or at birth. The infectious dose is unknown. Healthy adults are usually not affected but may experience mild to moderate flu like symptoms.
Infection in pregnant women may be mild and a temperature before or during birth may be the only sign. However, the infection can be transmitted to the foetus through the placenta which can result in stillbirth or premature birth.
In immunosuppressed patients, listeriosis usually presents as a brain inflammation, brain abscess or bacteraemia. Pneumonia, endocarditis and granulomatous lesions in the liver and other joints have also been described.
Prevention and treatment
It is not possible to test for listeriosis in people who may have been exposed to listeria but are not showing symptoms. Early recognition and treatment in symptomatic people is important in high risk groups, such as pregnant women and immune-compromised people.
If listeriosis is suspected in a high risk person, immediate testing (blood or stool cultures) should be undertaken. Immediate treatment with intravenous antibiotics should be considered in consultation with your local infectious diseases unit in high risk symptomatic patients. It is important to educate people in high risk groups about the foods likely to be contaminated, and about safe food handling and storage. See the Better Health Channel's advice on Listeria food poisoning for more information.
health.vic - Listeriosis
Medical practitioners and laboratories are required to notify all confirmed cases to the Department of Health and Human Services within five days of confirmation via health.vic's Notify a condition now section.
Better Health Channel - Listeria
Human illness: Communicable Disease Prevention and Control section at the Department of Health and Human Services on 1300 651 160 (24 hours).
Food Safety and recalls: Food Safety Unit at the Department of Health and Human Services on 1300 364 352.
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