In a notable development, six dairy farms in Nevada have been identified with a new strain of the H5N1 bird flu virus. This strain, called D1. 1, is different from the one that has been seen in other dairy herds across the US, specifically B3. 13. D1. 1 has previously only been found in birds and people who had close contact with them. This marks the second time that bird flu has jumped from birds to cattle, raising concerns about how easily the virus can spread.

   The situation is concerning because controlling the virus spread among cows is easier than controlling it from birds to cows. Experts worry that this new development could change how efforts to contain the virus are handled. This new strain has caused severe infections in two people: a teenager in British Columbia and a senior in Louisiana. Farm workers in Washington State who were in contact with infected poultry also tested positive, but their symptoms were less severe.

   State officials in Nevada are closely monitoring the situation. The affected dairy farms have provided contact information for their workers, who are being watched for any signs of infection and given protective gear. So far, no human cases have been linked to these infected herds.

   The new strain, D1. 1, is not causing more severe symptoms in cows than the B3. 13 strain. Cows infected with D1. 1 show similar symptoms, such as loss of appetite and reduced milk production. Most cows recover with proper veterinary care. This is similar to what has been observed since the outbreak began in Texas and Kansas.

   The newly infected herds in Nevada were discovered on January 31 through a USDA program that tests milk from large silos across the country. This program helps trace the origin of the infection by testing milk from multiple farms that come into a single silo.

   Experts are raising important questions about how dairy cattle are getting infected and whether the outbreak can be contained. Since March 2024, the H5N1 avian influenza has been detected in 957 herds across 16 states. Although the risk to most people is still low, 67 human infections have been confirmed in the US, mostly among farm workers who had contact with infected animals.

   The spread of the virus among animals and birds is a concern, especially as it evolves and adapts. It is important to understand how these infections are being passed between animals and to develop strategies to protect both animals and humans.

A Worrying Spread: Bird Flu in Nevada Dairy Farms

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