The Cow Flu: A New Threat to the Global Health

Tuesday - April 9 2024, 04:29 UTC - 7 months ago

A dairy worker in Texas tested positive for avian influenza, the second reported case in the United States. The virus is still mainly a bird virus and there is no evidence of easy person-to-person transmission. Scientists are working on creating genetically engineered animals resistant to the virus, but for cattle, options are limited. While there is no need to panic, caution is still advised as the virus has the potential to evolve into a major threat to human health.

On a farm in Texas, a dairy worker tested positive for avian influenza, the second ever reported case in the United States. The individual’s illness was mild and they are already recovering. While this may sound alarming, there is no need for panic as there is still no evidence that the virus can easily spread from person to person. So how did the worker become infected? .

The strain of avian influenza that has infected the dairy cows (H5N1) is a highly pathogenic virus that has been under close watch by scientists for its potential to cause a pandemic. This is not the first time that avian influenza has infected humans - the first reported case was in 1997 in Hong Kong, where 18 people were infected and 6 died. However, what is concerning is that these viruses have been infecting not just birds, but a variety of other species as well.

Several spillover cases of avian influenza have been reported in recent years, affecting animals such as minks, skunks, raccoons, coyotes, seals, sea lions, and bears. But what makes this new case in Texas significant is that it is the first time avian influenza has been found in domesticated mammals that frequently come into contact with humans. According to Richard Webby, a virologist at St. Jude Children’s Research Hospital, the effects of avian influenza on cows and its potential for transmission from cow to cow are still unknown.

Despite the fact that the virus is infecting dairy cows and the recent case of a dairy worker, Webby reassures that this is still predominantly a bird virus. Genetic sequencing by the USDA and CDC has found that the strain of flu responsible for these new infections is nearly identical to the one circulating in wild birds. And while there have been some genetic changes found in the virus, they are not significant enough to make it easier to spread in mammals.

So how are the cows becoming infected? While cow-to-cow transmission has not been confirmed, it is suspected to be occurring. However, unlike the traditional way flu spreads through coughs and sneezes, this transmission may be indirect. Webby explains, "An infected cow drinks from a trough of water and the next cow comes along and drinks from that same trough." .

As a long-term solution, scientists have been working on creating genetically engineered animals that are resistant to avian influenza. Last year, researchers successfully created chickens with enhanced resistance to the virus using CRISPR technology.

But for cattle, the options to curb transmission are limited. Culling cattle would be a much harder decision due to their higher value compared to chickens, and currently there are no vaccines available for cows. However, Webby assures that they would be relatively easy to produce.

While it may seem like avian influenza is becoming more prevalent, this isn't necessarily true. With more cases being reported globally, there are more opportunities for the virus to undergo genetic changes that could make it easier to infect humans. However, it is important to note that there is currently no cause for panic. As Jessica Hamzelou explains in a previous issue of The Checkup, there are still several key factors that would need to align for bird flu to become a major threat to human health.

In the meantime, scientists are using tools like Google Earth to visualize the movement of H5N1 and potentially improve their ability to predict where outbreaks may occur in the future.