Avian Botulism is a disease affecting birds that's on the rise in Aotearoa New Zealand. We've had outbreaks of the disease here in Kāpiti in recent years, as have Horowhenua, Auckland and Waikato regions.
With rising temperatures and more sporadic rainfall we're likely to see more outbreaks of the disease in the future.
Avian botulism is a disease that causes paralysis in birds and often kills them. The disease is caused by Clostridium botulinum, a bacteria that's around in the environment all year round. When low water levels, low oxygen levels in ponds and waterways, poor water quality/pollution and warm temperatures combine, the bacteria can quickly reach toxic levels.
Birds contract avian botulism when they eat maggots that have fed on the bacteria. Freshwater fish and eels can also be poisoned when the bacteria reach toxic levels.
A severe outbreak of avian botulism can kill hundreds of birds, eels and fish. The outbreak usually declines once cooler weather and rainfall arrives.
Avian botulism is spread through maggots which contain the pathogen. Birds don’t spread the disease to one another while they are alive, but if they die with the infection, other birds can contract botulism through maggots from the dead birds. Waterfowl are particularly susceptible, because the bacteria is often found around ponds and waterways. This is often where an outbreak begins.
There seems to be a low risk to human health from avian botulism, but it can make dogs and cats, as well as other domestic pets, very sick.
- let your pets eat dead fish, eels or birds
- handle dead fish or waterfowl with bare hands – always wear gloves
- harvest or eat birds, eels or fish from areas where botulism is present.
When there's an outbreak, we work to contain it by:
- removing dead animals from Council-owned land, to break the maggot cycle and slow the spread
- working with other agencies and organisations including Greater Wellington and HUHA in combating the outbreak
- putting up signs in affected areas, warning about what’s happening and what you should do
- planting and other restoration techniques that help improve water quality.
- Avoid feeding ducks – it’s better to allow them to forage naturally.
- Don't feed them bread – when it rots in the ponds it promotes the growth of botulism bacteria.
- Pick up your pet’s waste and dispose of it properly
In an outbreak, you can help us contain the spread:
- If you have wetlands on your property and you find dead birds or other animals on or around the water, remove the carcasses and bury them about 70 centimetres deep.
- Always wear gloves when handling the dead animals, and your wash hands with soapy water afterwards.
- Let friends and whānau know how they can help reduce avian botulism.