It has been five years since the COVID-19 pandemic began, drastically altering our way of life, only to find us in the grip of fear over yet another infectious agent causing alarm all over the world. This time, it’s the H5N1 bird flu, a disease that health officials in Asia, particularly India, have been closely monitoring for several years. Only very unsettling is the abrupt turn it has taken, particularly in North America, where previously unknown capabilities of this virus have clearly revealed themselves.
Unprecedentedly, H5N1 began spreading among dairy cattle in early 2024, being the very first time to plague the cows across the world. By March, California, the state responsible for massive dairy production, declared a state of emergency thanks to virus affliction over 660 farms. This unexpected behavioral change raises alarm bells that H5N1 could be evolving with planetary effects as far as health is concerned.
But the virus has gone even outside for farms. The wildlife across North America has also been at the receiving end of this outbreak. A wild animal sanctuary in Washington has reported 20 large predators—tigers and lions—dying from H5N1. This juxtaposes a continuing trend of mortality from the virus in seals along coastlines, foxes in forests, and the outbreaks even extended to bears within national parks, which only underscore the trend in ever-increasing mammalian activity, an unheard-of sort in H5N1’s history.
The demonic history of H5N1 dates back to 1997, when the virus first shifted to humans from birds during a poultry outbreak in Hong Kong, leading to six known deaths and the culling of 1.5 million chickens. Up to now, it has infected over 900 across the world, with over half of those cases resulting in death. Infections predominantly occur by direct contact with sick birds and severe symptoms in these cases tend to predominate.
However, a curious shift has been noted in recent cases: many infections now cause only mild symptoms.
65 people, most of them dairy workers with contact with infected cattle, tested positive in the United States in 2024. All but one had mild disease. Scientists speculate it is because of better reporting of mild cases or that the strain spreading in cattle is less dangerous to humans. Still, two cases that were serious late in the year have raised the alarm.
A Canadian teenager in November started showing seremes for respiratory illness. Late in 2004, a severe case was reported in a man exposed to backyard poultry. The lovebirds being each case showed mutations enhancing their binding to human lung cells, which are a concern for virologists.
Despite these worrying mutations, H5N1 still struggles to transmit among humans due to binding essentially avian-specific receptors. These are rare in human airways, and this particular property still restricts the virus from causing a pandemic.
To minimize risk, health experts advise against contact with sick or dead animals, the consumption of only pasteurized dairy products, and the avoidance of keeping pets near wild birds. This advice becomes even more highly revolutionary in countries such as India, where traditional farming practices compounded by live bird markets may elevate the risks of exposure.
As we head into 2025, the world faces a serious challenge. For H5N1, human-to-human transmission has yet to get underway; however, the prospect of an increased risk is present as it develops within other species. It is also possible, given the piece of mixing with human flu strains, that a more virulent strain may arise.
Source : dnaindia.com
