Avian flu suspected in deaths of 3 swans in Stratford, Ont.

Stratford, Ont., officials believe H5N1 avian influenza is behind the recent deaths of three of its dearest mute swans.

Quin Malott, the city's parks, forestry, and cemetery manager, said the first swan was found dead in the Avon River on Saturday, but his team didn't connect the dots until two other swans got sick on the following days. 

"We didn't think much of it at that point because it was just the one bird, and then Sunday we saw another one was looking a little lethargic, the same on Monday, and they both ended up passing away," Malott said. 

Malott said the pond that the swans use is frequented by a lot of wild ducks, and believes the flu might have been brought in by one of them. Although testing is underway to confirm cause of death of the swans, Malott said their local veterinarian and avian pathologists at the University of Guelph believe avian flu is the most likely scenario.

Beth MacDougall-Shackleton, a biology professor at Western University in London, Ont., said the deaths appear to be a case of the flu, which is especially harmful this year to birds that get infected. 

"Avian flu is always circulating in wild birds and domestic birds just like the human flu is always circulating among us, but it's a nasty disease, this pathogenic version of it," she said.

Human activity, gatherings causing spread

MacDougall-Shackleton said signs a bird may have avian flu include:

• Not moving around as much or reacting to human activity around them.
• Shaking with tremors and losing co-ordination.
• In the final stages, they may be gasping for air, struggling to breathe.

MacDougall-Shackleton said the disease is transmitted by direct physical contact with an infected bird, its feces or secretions, and that spring and fall tend to be prime seasons for the flu.

"Any time we have a lot of birds coming into close contact, especially if it's birds of different species, we see a big spike in transmission."

Malott said the ability of the virus to spread quickly is hard to control, and added that so far, it hasn't spread to any other swans. 

"We have birds on the river with all kinds of wild foul around them, so it could be one duck that's a carrier, and just the way it might interact with one swan that's in an enclosed area with other swans, it's going to spread quickly," he said.

Human interaction with wild birds may seem harmless, but it can contribute to the spread of flu because it encourages birds to gather together, MacDougall-Shackleton said. 

"As humans, what we do affects the behaviour of everything around us, so if we set out mass feeding stations that attract migratory birds, or even if you're simply feeding bread and encouraging them to congregate around you, you're bringing them into close contact."

Malott said Stratford residents have been co-operative when told about the dangers of mass bird feeding. His staff will start feeding the swans indoors and are considering enclosing the area to ensure wild animals don't get in.

Although MacDougall-Shackleton expects a spike in transmission before migration season ends by late October, she said there should be fewer cases once birds have migrated south.