Experts warn of bird flu's escalating pandemic potential

Health experts are raising alarms about the growing pandemic threat posed by bird flu, particularly the H5N1 strain, which has shown signs of mutating and spreading to new hosts, including cows and humans in the United States.

First identified in China in 1996, the H5N1 variant has become a global concern over the past four years, spreading to previously untouched regions like Antarctica. According to the World Organisation for Animal Health, over 300 million poultry birds have been culled or killed since October 2021, and the virus has caused the deaths of wild birds across 79 countries. Mammals that consume infected birds, such as seals, have also experienced mass die-offs.

In a concerning development earlier this year, the virus began infecting dairy cows in the United States - a first in its transmission history.

The Centers for Disease Control and Prevention (CDC) reported 58 human cases of bird flu in the US this year, including two with no known exposure to infected animals. Research last month found that 7% of dairy workers tested in Michigan and Colorado had antibodies for bird flu, suggesting possible undetected cases.

Meg Schaeffer, an epidemiologist with the SAS Institute, warned that bird flu is "knocking on our door" and could spark a new pandemic.

While the H5N1 virus has not yet adapted for efficient human-to-human transmission, scientists warn it is close to achieving this capability. Research published in Science revealed that the strain currently infecting cows in the US is only one mutation away from becoming more transmissible among humans.

Virologist Ed Hutchinson of the University of Glasgow noted that genetic sequencing from a Canadian teenager sick with bird flu last month indicated the virus might be evolving to better bind to human cells. However, barriers to widespread transmission still exist.

"The more species the virus infects, the higher the likelihood of it adapting to humans," Schaeffer cautioned.

If a bird flu pandemic occurs, it could be severe due to humanity's lack of immunity to H5N1. Nearly half of the 904 recorded human cases since 2003 have been fatal, according to the World Health Organization.

However, there is reason for cautious optimism. Antiviral treatments and vaccines for bird flu already exist, setting it apart from the unpreparedness during the early days of COVID-19, noted Tom Peacock, a virologist at Imperial College London.

To minimize risks, researchers have urged the US government to increase surveillance, enhance inter-agency communication, and ramp up testing. The Department of Agriculture recently announced plans to test the national milk supply for bird flu, particularly raw milk, which has been found contaminated in past outbreaks.

The discussion around raw milk has added another layer to the issue. Despite its known risks, raw milk advocates, including California producer Mark McAfee, have pushed for relaxed regulations. Schaeffer criticized this stance, calling it a "terrible idea" that could endanger public health.

Experts stress that proactive measures and coordinated efforts are essential to prevent a potential bird flu pandemic, which could have catastrophic global consequences.