New Delhi, March 26 -- Infectious disease outbreaks have a bad habit of piling on at the worst possible times.

The 1918 flu pandemic, also known as the Spanish flu, caught the world by surprise just as the First World War was coming to an end. It was responsible for killing three to five per cent of the world's population (50-100 million people, equivalent to about 400 million today).

Now, as we reflect on five years since the declaration of the COVID-19 pandemic and face economic uncertainty imposed by the United States administration - as well as lingering conflicts in places such as the Middle East and Ukraine - it's the steady march of avian influenza, or "bird flu," that poses an imminent threat to humanity.

Bird flu has been caus...