Former Centers for Disease Control and Prevention (CDC) Director Robert Redfield has predicted that the next pandemic could be from bird flu and it's just a matter of when that will be. Notably, Mr Redfield was speaking with a news channel to discuss the growing concern for bird flu as the virus continues to spread across cow herds in the US.
''I really do think it's very likely that we will, at some time, it's not a question of if, it's more of a question of when we will have a bird flu pandemic,'' Mr Redfield said.
He also noted that bird flu has a ''significant mortality'' when it enters humans compared to COVID-19.
While the mortality rate was 0.6 per cent for Covid-19, Mr Redfield said the mortality for the bird flu would probably be ''somewhere between 25 and 50 per cent.''
Last month, US officials reported the country's third human case of bird flu linked to the current outbreak of the virus in dairy cattle. Worldwide, doctors have detected 15 human infections caused by bird flu strain H5N1.
While there is not yet evidence that the virus is spreading between humans, Mr Redfield explained that there must be five amino acids present for bird flu to gain a propensity to bind to a human receptor ''and then be able to go human to human'' like Covid.
''Once the virus gains the ability to attach to the human receptor and then go human to human, that's when you're going to have the pandemic. I think it's just a matter of time,'' he added.
It's unknown how long it will take for the five amino acids to change, but Mr Redfield said he is concerned because it's being detected in cattle herds across the US.
''I know exactly what amino acids I have to change because in 2012, against my recommendation, the scientists that did these experiments published them. So, the recipe for how to make bird flu highly infectious for humans is already out there,'' he said.
Over the past few years, the highly pathogenic avian influenza virus has spread to infect more than 50 animal species, including, from March, dairy cattle in the United States.
Unlike in Europe, American farmers are allowed to feed cattle ground-up chicken waste, which some scientists say may be a risk factor for bird flu -- though the feed industry has challenged this claim and US authorities believe wild birds are responsible for infecting cows.
