The bird flu virus wreaking havoc around the world appears to be in U.S. cows, This virus subtype has been recorded in cattle for the first time. On March 25, three U.S. states (Texas, Kansas and New Mexico) reported that cows were infected with what scientists believe is the same H5N1 influenza virus that has killed hundreds of millions of poultry and wild birds.
Livestock infections are affecting milk and causing limited disease in most older animals.They were also discovered Some farms have dead birds, which may explain the origin of the virus. Public health officials stress that the risk to humans from the virus remains low.
So-called highly pathogenic avian influenza (HPAI) viruses have been documented spreading among birds Infects dozens of other mammalsbut rarely spread between them.
Gregory GrayEpidemiologists at the University of Texas describe new testing results for dairy cows in several states as A “worrying” fact Because this may indicate that this avian influenza virus is Transmitted directly from livestock to livestock, rather than being transmitted by birds, and has mutated in a way that allows it to better infect humans. But the National Veterinary Services Laboratory explained in a statement that preliminary studies of affected cows showed no signs that the virus had changed.
Likewise, the U.S. Department of Agriculture (USDA) is not requiring farmers to cull affected flocks, as it did when the virus hit poultry farms. USDA officials stress that pasteurization kills the virus in any milk produced by infected cows.
Others of the four influenza viruses are known to infect livestock, but this is the first highly pathogenic avian influenza virus to cause illness in livestock. Only Texas has officially confirmed that the avian influenza found in its cows is of the H5N1 subtype, and these three states have not yet reported whether it is the clade responsible for widespread bird mortality, 2.3.4.4b.The USDA detailed in a statement, “Testing in Texas shows Consistent with strains observed in wild birds” And federal and state scientists are working to quickly complete genetic testing.
May be spread through the air
In a report published in the journal Science, Gray discussed the detection of avian influenza in cattle, explaining that it was concerning and disturbing, “We need to address this issue because If the virus continues to change, may spread to other species, including humans. “
However, experts are not terribly surprised by this finding.As he explains, “these influenza viruses they keep changing and there is fairly strong evidence that all four types Infected livestock for many years“. In fact, “a very good report came out in 2019 suggesting that there may be something in cattle that makes them somewhat immune to severe disease and transmission. ” But today, “ things have changed because There are animal disease epidemics in many states, and the probability of transmission from cow to cow and farm to farm is much greater than before. “
In this sense, regarding direct transmission between livestock, he pointed out that it is still unclear. “I don’t think anyone has done these experiments, and I think that’s going to be one of the things that needs to be investigated fairly quickly.” “I think given the rapid spread between states, there are some indications that Can spread through the air“.
On the other hand, he concluded by commenting that regarding infection through birds, it could be due to multiple routes, e.g. Shared and contaminated water.