Australia Listeriosis outbreak linked to cantaloupe: Seven deaths reported
In an update on the Listeriosis outbreak in Australia linked to the consumption of rockmelons (cantaloupe) from a single grower, health officials report that since mid-January 2018, 20 outbreak cases (19 confirmed and 1 probable) of listeriosis were reported to date.
All the cases required hospitalization and there have been seven deaths and one miscarriage associated with the outbreak.
On Feb 27, an Australian grower of rockmelons recalled all fruit tied to the outbreak, but not before some fruit was distributed to eight countries: China, Japan, Kuwait, Malaysia, Oman, Qatar, Singapore, and the United Arab Emirates.
On 4 April 2018, it was reported that more than 30 samples of melons from the grower through the supply chain, including retail and on farm, tested positive to Listeria monocytogenes. Additional testing found L. monocytogenes in the packing area. All L. monocytogenes samples had the same genetic sequence as the human cases.
It is believed that the cause of the outbreak was a combination of environmental conditions and weather contaminating the surface of the fruit, with low levels of the bacteria persisting after the washing process. The grower continues to work closely with the relevant authorities and has returned to supply rockmelons (during the week starting 2 April) after testing cleared the property.
People who are at an increased risk of listeriosis include those who have immunocompromising illnesses, the elderly, pregnant women and their fetuses, newborn babies or people on immunosuppressive drugs.
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.
Image/CDC-Jennifer Oosthuizen
