Avian botulism outbreaks: what dog owners and pet professionals need to know
Sussex Wildlife Trust has reported a suspected avian botulism outbreak at Rye Harbour Nature Reserve, with a number of dead birds found there in recent weeks. It's a pattern being seen elsewhere in the UK too - Bristol City Council flagged an outbreak at St George Park in early August, and Richmond's parks team confirmed suspected cases at Barnes Pond around the same time. All point to the same cause: this summer's hot, dry conditions.
What is avian botulism?
Avian botulism is caused by a naturally occurring toxin, produced by bacteria that thrive in warm, low-oxygen conditions. When water levels drop during hot, dry weather, still water heats up and stagnates, creating the perfect environment for the toxin to develop. It mainly affects wild waterbirds, causing paralysis that leaves them unable to walk, swim or fly - which is often how an outbreak is first spotted. Outbreaks can last several weeks and, without intervention, may recur in the same location.
What's the actual risk to dogs?
Botulism itself is rare in dogs. The real risk during an outbreak comes from two specific routes: a dog eating an infected or dead bird, or drinking from water contaminated with the toxin. Simply walking near an affected lake isn't the concern - direct contact with the water, or with a sick or dead bird, is.
Because of this, the risk is very manageable with the right precautions, but it's worth taking seriously in an active outbreak area rather than assuming it won't apply to your dog.
Symptoms to watch for
Botulism causes a progressive, ascending paralysis - meaning it typically starts at one end of the body and works its way along. In dogs, this usually looks like:
Weakness or wobbliness starting in the back legs, which can progress to the front legs
Drooling or a dry, sticky mouth
Difficulty chewing or swallowing, sometimes with gagging
Drooping of the face or reduced blinking
In more advanced cases, difficulty breathing
One important thing to know: dogs remain fully alert and aware throughout, even as physical symptoms progress. This can make early signs easy to dismiss as tiredness after a walk, so it's worth taking any unexplained weakness seriously, particularly after time near water.
Symptoms can appear within hours of exposure and progress quickly, so any suspected case is a same-day emergency vet visit rather than a wait-and-see situation.
Where outbreaks have occurred
Alongside Rye Harbour, this summer has already seen reported or suspected cases at:
St George Park, Bristol
Barnes Pond, Richmond upon Thames
Councils and wildlife trusts have both noted that similar incidents are being reported in other parts of the country as the dry weather continues, so it's worth checking local wildlife trust or council updates for your area before visiting lakes, ponds or reserves with a dog.
Keeping dogs safe
Keep dogs on a lead near any water where cases have been reported
Don't allow dogs to swim, paddle or drink from affected water
Never let a dog approach, sniff or pick up a sick or dead bird
Report any dead or visibly ill birds to the DEFRA helpline on 0345 933 5577, rather than handling them directly
For dog walkers, home boarders and anyone else with dogs in their care, a quick check of local outbreak reports before a walk is a small step that makes a real difference. Supporting pet professionals who care means keeping you across updates like this one, so you can make informed decisions for the animals you look after.
