Here we go again, is everyone ready for a round 2 of lockdowns they slowly introduce it then take your freedoms away, then jab you with chemicals. The bird flu viruses have primarily circulated in birds for a long time. However, in December 2023, an outbreak occurred in U.S. dairy cows, despite cattle not typically being susceptible to avian influenza A. In late March, a U.S. dairy farm worker was infected by an H5N1 virus from a cow. On May 22, a second human case of H5N1 infection was reported, linked to exposure to infected dairy cows in Michigan. That same day, an Australian child was infected by an H7 strain, another subtype of influenza A known to affect humans.
Bird flu outbreak in U.S. dairy cows since bird flu infections in humans are rare, these incidents have raised significant concern among scientists. Why is this happening, and how concerned should we be? This article aims to avoid unnecessary fear about a potential future pandemic. Instead, we encourage rational thinking and appropriate adjustments for the future.
Rapid Spread in Birds
The H5N1 virus family traces back to 1996 when it was first discovered in a sick goose in Guangdong province, China. Over time, H5N1 has evolved, resulting in different genetic lineages (clades) as they mutate. In 2013, the H5N1 clade 2.3.4.4b emerged and spread rapidly across nearly 100 countries, becoming the dominant clade and causing significant losses to the poultry industry. By December 2021, this clade was first identified in wild birds in the United States. It quickly mixed with other circulating influenza A viruses in North America, leading to viral reassortment and recombination, causing severe illnesses in mammals.
The Jump to Cows
Avian influenza viruses, commonly called bird flu viruses, belong to the flu virus family, which has many natural hosts, including ducks, geese, swans, gulls, pigs, and horses. Typically, certain flu viruses infect specific hosts and do not jump from one host to another. However, the H5N1 clade 2.3.4.4b became concerning due to frequent spillover events, where a virus jumps from its normal host to a new species. Since December 2023, H5N1 clade 2.3.4.4b viruses have spread to dairy cows in multiple U.S. states, according to the USDA and CDC.
By early this year, some cows were producing less milk and eating less. It was later confirmed that H5Nx clade 2.3.4.4b viruses were present in both the cows’ milk and nasal samples. The USDA reported the first outbreak of this clade in cows. By May 28, 67 herds were infected by the H5N1 virus in nine states. This indicates a significant expansion of host tropism, with potential implications for human health.
The Likely Jump to Humans
Although bird flu infections in humans are rare, they do occur. Over the past 20 years, there have been 888 human cases of H5N1 infection across 23 countries, resulting in 463 deaths. Most cases have occurred in Egypt, Indonesia, and Vietnam, with a case fatality rate exceeding 50 percent. In April 2022, the first known case of H5N1 infection transmitted from poultry to a human in the United States was confirmed in a Colorado poultry worker.
In late March, a dairy farm worker in Texas was confirmed to be infected with the H5N1 clade 2.3.4.4b virus after showing symptoms of hemorrhagic conjunctivitis. This was the first reported case in the United States of the H5N1 virus transmitting from a mammalian species to a human. These cases suggest the virus may have acquired the ability to spread between mammals and potentially infect humans.
If H5N1 were to develop the ability to spread easily among humans, it could have a significant impact on the population, given the high mortality rate observed in previous cases. With only two confirmed U.S. cases of cow-to-human transmission, the full extent and mortality rate of similar infections remain unknown.
A Severe, Rapidly Spreading Virus
Increased pathogenicity of H5N1 in animals has been noted. For example, a 2023 study found that a much lower dose of H5N1 caused severe illness and death in macaques compared to studies conducted 10 to 23 years ago. This indicates a dramatic increase in the pathogenicity of the virus.
There has been longstanding criticism of gain-of-function research. In 2011, Paul Keim, a microbial geneticist, expressed concern about the potential dangers of such studies. Richard Ebright, a molecular biologist, also voiced concerns about the risks of generating new, dangerous virus strains through research.
Bird flu viruses, particularly the H5N1 clade 2.3.4.4b, have shown increased ability to infect mammals and potentially humans. While it is crucial to monitor these developments, it is equally important to avoid unnecessary fear and focus on improving public health through rational thinking and appropriate adjustments.
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