Dunedin (Monday, 27 January 2025) – The Dunedin City Council has identified Avian Botulism, a disease that causes paralysis in birds and often kills them, at the Waikouaiti wastewater treatment plant, which is located close to the Waikouaiti Estuary. It is unrelated to the Avian Influenza but is being treated as a significant animal welfare issue.

The disease has caused the death of hundreds of ducks so far, which have been found in and around the oxidation ponds at the treatment plant. This issue was first identified on Tuesday, 21 January 2025. Deceased birds were sent to the Ministry of Primary Industries (MPI) for testing that identified the contraction of the Avian Botulism type-C strain by the birds.

The Medical Officer of Health has confirmed that the risk to human health is very low and Botulism in wild birds has not been known to cause botulism in humans. The DCC is recommending and taking some precautionary measures to mitigate the outbreak.

The DCC is actively working alongside Otago Fish & Game, MPI, Department of Conservation (DOC), and Otago Regional Council to minimise the risk.

Bird health is regularly monitored at treatment plants in Dunedin with Avian Botulism a known risk at water bodies, such as treatment ponds, across New Zealand. This is the first recorded event at a Dunedin plant, with outbreaks being more common in the North Island.

DCC has activated its management plan for collecting and disposing of dead birds and will continue for the next few weeks. This should help stop the spread and break the chain of infection.

Advertisement - scroll to continue reading

Otago Fish & Game and DOC are conducting surveillance of birds across Dunedin city for signs of any further spread.

The treatment plant is fenced off and the risk to human health is believed to be very low. As a precautionary measure, people visiting the Waikouaiti estuary are advised to take the following precautions:

· Don’t let your pets eat dead wild birds or fish

· Don’t touch or handle sick or dead wild birds or fish

· Don’t eat undercooked or improperly prepared waterfowl or fish. Heating the food properly will kill the toxin

· Don’t harvest birds that appear to be sick or dying

· Maintain good hand hygiene. Wash your hands either with soap and running water or use alcohol hand rubs often and thoroughly — especially before and after contact with animals and their environment.

Avian Botulism is caused when waterfowl eat the toxin produced by the Clostridium botulinum bacteria. The bacteria occurs naturally in soils around ponds and wetlands and is found in oxidation ponds. It is harmless until certain environmental factors occur, such as low oxygen and warm temperatures. It is not related to Avian Influenza and the type-C strain identified poses minimal risk to the health of humans.

Anyone who is worried about the impact on their health can call Healthline for free on 0800 611 116.

If you see three or more sick or dead wild birds in a group, report it immediately to Biosecurity New Zealand's Exotic Pest and Disease Hotline on 0800 80 99 66.

Sick or injured wildlife should be reported to the DOC wildlife hotline 0800 362 468.

© Scoop Media