A strain of avian influenza, known as H5N1 or highly pathogenic avian influenza, has sparked concerns in cattle herds across the United States in recent weeks. This development has raised significant alarm among health experts. The Chief Scientist at the World Health Organization (WHO) warned of the high mortality rate associated with the virus in humans.
As of now, the virus has affected more than 20 clusters in eight states of the U.S since a surge was initially reported last month.
The states that have been impacted so far include Idaho, Kansas, Michigan, New Mexico, North Carolina, Ohio, Texas, and South Dakota.
Moreover, on April 1st, the Centers for Disease Control and Prevention (CDC) confirmed that the virus had spread further in Texas and had infected individuals who were exposed to dairy cows.
Experts are emphasizing the need for extreme vigilance, investigation, and situational assessment due to the rapidly changing individual risk scenarios.
Infection of cattle is unprecedented.
This virus is not new – H5N1 was initially detected in 1996 in waterfowl in southern China. A new version of the H5N1 virus became widespread in 2021 and has continued to infect both wild and domestic bird populations globally.
Spread to other animals has occurred occasionally as the virus has crossed into various mammalian populations, including foxes, seals, sea lions, and humans, according to the CDC.
While the spread to mammals is a concern and can be fatal, past cases have shown that avian influenza typically stops spreading when it reaches mammalian populations, particularly humans.
However, in October 2022, a significant shift occurred when the virus spread from mink to mink at a mink farm in Spain, deviating from the usual transmission from birds to mammals. The USDA has confirmed that cows have been infected for the first time, and cow-to-cow transmission has contributed to the recent spread of avian influenza in dairy farms.
There is still uncertainty about how the disease spreads through cattle populations, with reports suggesting that the virus may be transmitted through milk due to high concentrations of the virus being shed in milk.
Is it safe to drink milk?
Most dairy products are pasteurized, which effectively eliminates the virus, making milk consumption safe for the majority of individuals. Drinking unpasteurized milk poses some risk, but experts suggest that even unpasteurized milk may be safe if not consumed immediately after milking.
The presence of the virus in milk raises questions about its transmission and impact on human health, as the virus is typically a respiratory disease.
How worried should I be?
The situation is under close monitoring by authorities, with several states implementing restrictions on dairy cow imports from affected regions. Scientists are analyzing virus sequences to identify genetic changes that could impact transmission and treatment effectiveness.
Concerns have been raised about the effectiveness of biosecurity measures on farms in controlling the spread of the virus. Experts emphasize the need for increased vigilance and monitoring to prevent further transmission.
Could H5N1 cause the next pandemic?
While there is uncertainty about the future, a widespread pandemic remains unlikely at this point. Authorities are prepared with stockpiles of vaccines and antiviral drugs effective against potential influenza strains.
There are two existing vaccine candidates against H5N1 available to manufacturers, along with several FDA-approved antiviral drugs. The focus remains on combating bird flu and preparing for any potential future outbreaks.
Experts continue to monitor the situation closely and emphasize the importance of staying informed and prepared for any developments.
About our experts
Jeremy Rothman is an Honorary Senior Lecturer in Virology at the University of Kent. His research focuses on infectious diseases’ pathogenesis and has been published in various scientific journals.
Matthew Hayek is an assistant professor at New York University, specializing in the impact of food production on climate change, ecological processes, and the spread of zoonotic diseases.
Source: www.sciencefocus.com
