The first wave of bird flu is the worst: What can Australia learn from overseas?

The H5N1 strain of bird flu is causing alarm as it spreads rapidly across Australia, with hundreds of dead birds reported in recent reports. This is the first wave of the virus, which emerged in 2020 and began spreading widely by late 2021. Despite Australia remaining free of the virus until now, the severity of the first wave has been observed in other countries, such as Europe and North America.

The current strain is highly pathogenic, infecting various organs, including the central nervous system, leading to neurological disease and death. It has also been found to infect mammals, including foxes, deer, sea lions, and even livestock like cattle. Human infections are rare, and there is no evidence of person-to-person transmission so far.

While the initial wave can result in high mortality rates, often ranging from 25% to 76% in breeding-age adult birds, the impact varies among populations and individuals. Some species recover better than others, with younger and more vulnerable birds often being the first to die off in the first wave, giving way to more resilient survivors.

Recovery for highly susceptible species can take decades, if not longer. However, experts in Australia have taken proactive measures, such as expanding surveillance, developing action plans, and implementing vaccination programs for captive and closely managed populations. While there is no guarantee of preventing catastrophic destruction, the combination of factors including exposure, resistance, and coping mechanisms will ultimately determine the fate of various species in Australia.