In the United States, there has been an outbreak of bird flu among dairy cows for some time. So far, 33 farms in eight states have been affected.
The first case was reported on March 25. According to the association, this is the first time that a highly contagious bird flu disease has been confirmed after natural infection in livestock. A few weeks before cases were discovered among ruminants, kittens in Minnesota were also infected.
Dairy cows lost milk production, ate less feed, and were lethargic, dehydrated, and feverish. The milk of sick animals should also be thicker than normal and resemble colostrum. The cows' feces should also be abnormally sticky or loose, the SVA wrote.
Not in Europe
In infected animal populations, the incidence of the disease is estimated at about ten percent, but symptoms are transient. Viruses have been found in milk samples and throat samples. It has been shown to be the same type of highly pathogenic avian influenza H5N1 (category 2.3.3.4b) that has infected birds in the USA and Europe. However, the SVA wrote that the virus that infected cows in the United States carries more genetic fragments from the American gene pool of influenza A virus genotype that have not been detected in Europe.
In the United States, they are working hard to investigate cases of infection and reduce the risk of its spread between states. From April 29, testing of animals will be mandatory if they are to be transported between different states. Only those who can leave a negative test may be transferred, the USDA wrote.
Low risk to humans
The USDA determined the disease spread among cows in the same herd, spread from cow to poultry, spread between dairies in connection with cattle movements, and even cows with no clinical symptoms tested positive.
Furthermore, the USDA wrote, it is important to remember that so far no changes have been found to the virus that would make it more transmissible to humans or between humans. However, cases are possible among people who are in direct contact with sick animals. For example, one person was infected after coming into contact with livestock in Texas. But he developed mild symptoms, in the form of inflammation of the mucous membrane of the eye. The US Centers for Disease Control and Prevention (CDC) believes the risk to the public remains low. This is an assessment shared by the European Committee for Disease Control (ECDC).
Good recovery
The USDA also writes that affected cows recover after treatment and that the mortality rate is low. They also stress how important it is to have good biosecurity to limit the spread of disease to both livestock and poultry.
The FDA wrote that based on today's knowledge, they believe that commercial milk production is safe because of the pasteurization process and that the milk of sick animals has been destroyed.
The article was published on Friday, April 26, 2024
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