Sunday, November 3, 2024

Scientists and infectious disease experts warn about the growing danger of bird flu

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The disconnect between the warnings made by veterinary researchers and infectious disease specialists and the patchwork of toothless policies being offered against the threat posed by the evolving H5N1 bird flu virus to conciliate the public is widening at an alarming pace. 

Dr. Rick Bright, a virologist and former head of the US Biomedical Advanced Research and Development Authority, speaking with Fortune magazine, reminded readers that the virus “is going to adapt. We’ve watched it adapt over the years among bird species, and we know it is what influenza viruses do.”

Providing a backdrop to his comment, in the current bird flu panzootic period (2020-2024), 26 countries have reported information of infections among more than 48 animal species, including humans. Since the H5 strain was first identified, more than a half-billion farmed birds have been slaughtered. Wild bird deaths are estimated in the millions. Experts have warned that not only is it expanding its geographic range, but its adaption to immunologically naive populations will have tremendous impact on biodiversity, including the potential for the emergence of a pandemic in human populations. 

Since 2003, close to 900 people have tested positive for H5N1 virus, with slightly more than half dying (a lethality rate just above 50 percent). Since 2020, the number of cases has been considerably lower at 28, with eight fatalities (just under 30 percent lethality). While the current clade is seemingly less virulent, even this fatality rate, should H5N1 become a true respiratory pathogen in humans, would make the ongoing COVID pandemic pale in comparison. Many of these cases were among people with direct contact with birds and poultry. But the recent emergence of the disease in dairy cows and the transmission of the virus from these animals to humans raises the threat of the virus developing the necessary mutations to make direct human-to-human transmission possible. 

This is particularly concerning since the intimate connection between farm workers and animals in the agriculture industry makes such a scenario plausible. This type of zoonotic transfer was shown by the emergence of the COVID pandemic at the Huanan wet market in Wuhan, China in December 2019, a byproduct of the extensive wildlife trade there. 

According to the US Department of Agriculture, in the nearly three months since health officials and veterinarians began to hear about an unknown illness that was sickening cattle in the Texas panhandle, 94 herds have been infected across 12 states. These include Texas, Kansas, Michigan, Idaho, New Mexico, Ohio, North Carolina, South Dakota, Colorado and, last week, Minnesota, Wyoming and Iowa.

Number of dairy cow herds infected with H5N1 bird flu by week. [Photo: Data from USDA/WSWS]

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