Black Swans at Risk

Monday, 13 February 2023

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Black Swans at Risk

Avian Flu threatens Australia’s waterbirds

Apart from the COVID-19 pandemic, the world has been ravaged by another epidemic for the past few years — Highly Pathogenic Avian Influenza has been affecting the birdlife in both the Northern and Southern Hemispheres, with its lethal effects impacting huge numbers of waterbirds and other species. Fortunately, the ‘tyranny of distance’ has spared Australia from being afflicted — at least so far.

It appears that the Highly Pathogenic Avian Influenza, often simply referred to as ‘bird flu’, is particularly contagious among waterbirds. Although many of the infected birds die, others are still able to fly, with some even capable of undertaking extensive migratory movements, infecting other birds in the places they migrate to, as well as along their migratory routes. It is a highly contagious disease.

However, few waterbirds migrate to Australia from bird flu hotspots, so our ducks, swans and the like have not yet been exposed to the virus.

Recent research—which examined the genome of the Black Swan—has indicated that, if bird flu were to reach our shores, Australia’s population of Black Swans could potentially be decimated due to a particular genetic absence which manifests as a reduced immune response.

Because Black Swans have lived in isolation from many pathogenic infections that have afflicted birds overseas, their ‘naïve’ immune systems leave the birds especially vulnerable to infection by bird flu, as they are highly sensitive to the virus. Experts from the University of Queensland say that infected birds can die within three days of contracting the disease, and that the effects on a population scale could potentially be catastrophic for Black Swans in particular.

Bird flu has spread from Asia across to Europe and North Africa, as well as to North and South America, and in each region, many thousands of birds have died as a result, as their naïve immune systems were unable to cope with the infection.