US dairy cows infected with H5N1 avian influenza virus surprise scientists

[New Sancai Compilation First Edition] Influenza is usually considered a respiratory disease, but according to US news media reports, there were cases of H5N1 avian influenza virus accidentally infecting dairy cows in the United States this year, which surprised American scientists. Busy.

The H5N1 virus was first discovered in 1959 and has since evolved into an epidemic disease of migratory birds and poultry, and is highly lethal. What’s even scarier is that the virus has been changing over the past few years, spreading to more and more animals, including two of the most popular household pets, sea lions and polar bears, and now cattle.

The report said that although the virus can spread among different animals, scientists were surprised when cattle were suddenly infected this year, especially when the virus was found in the udders and milk of dairy cows. Bacterial infections in the udders of dairy cows are not uncommon, but the presence of the influenza virus is unexpected. The H1N1 swine flu virus that emerged in 2009 was limited to infecting the respiratory tract of pigs, while pork can still be eaten.

The U.S. Department of Agriculture’s Poultry Research Center and the National Animal Disease Center are therefore conducting relevant investigations and studies on viruses that appear in cattle. The researchers exposed four heifers, about one year old, to a mist containing the virus, while simultaneously spraying the virus on the teats of two other cows. They found that four cows exposed to the viral mist were infected with the virus but had few symptoms. The other two cows that had the virus sprayed on their teats became seriously ill, with a lack of appetite, reduced milk production, and the milk they produced turned light yellow and thick. Scientists at the center are also examining calves producing table milk to see if their blood is also infected with the virus.

Health investigators speculate that the virus is mainly spread through contact with milk containing the virus, or possibly through milking equipment, but it may also be spread by other means. However, they also said that because they do not know the complete process of dairy farm operations, they cannot draw conclusions yet. They only have a preliminary understanding of how the virus spreads.

Researchers are now testing a vaccine for dairy cows, but they say the work is still in the early stages of development, has not yet been approved for use, and is not guaranteed to eradicate the virus.

Scientists at the above-mentioned research units are also conducting research on pigs and other animals, trying to find ways to solve the avian influenza epidemic currently spreading among animals in the United States, hoping to find ways to block it. It is also trying to understand other ways in which the virus spreads between cows.

Their study also found a new, rare genetic combination in the avian flu virus that has spread to dairy cows, and researchers are working to figure out whether the virus can spread between cows.

The researchers pointed out that it is not yet known whether dairy cows have their own unique influenza, and whether the virus can be reciprocally transmitted between various animals and humans remains to be studied. They believe that finding answers to these questions is an important and urgent research topic.

(Compiled by: Mulian)

(Editor: Jiang Qiming)

(Source of the article: Compiled and published by New Sancai)