Dairy cattle in Nevada have been infected with a new type of that91裸聊视频檚 different from the version that has spread in U.S. herds since last year, Agriculture Department officials said Wednesday.

The detection indicates that distinct forms of the virus known as Type A H5N1 have spilled over from wild birds into cattle at least twice. Experts said it raises new questions about wider spread and the difficulty of controlling infections in animals and the people who work closely with them.

91裸聊视频淚 always thought one bird-to-cow transmission was a very rare event. Seems that may not be the case,91裸聊视频� said Richard Webby, an influenza expert at St. Jude Children91裸聊视频檚 Research Hospital.

A version of the H5N1 bird flu virus known as B3.13 was confirmed in March after being introduced to cattle in late 2023, scientists said. It has infected more than 950 herds in 16 states. The new version, known as D1.1, was confirmed in Nevada cattle on Friday, according to USDA. It was detected in milk collected as part of a surveillance program launched in December.

91裸聊视频淣ow we know why it91裸聊视频檚 really important to test and continue testing,91裸聊视频� said Angela Rasmussen, a virus expert at the University of Saskatchewan in Canada, who helped identify the first spillover.

The D1.1 version of the virus was the type linked to the first U.S. death tied to bird flu and a severe illness in Canada. A person in Louisiana after developing severe respiratory symptoms following contact with wild and backyard birds. a teen girl was hospitalized for months with a virus traced to poultry.

At least 67 people in the U.S. have been infected with bird flu, mostly those who work closely with dairy or cattle, according to the U.S. Centers for Disease Control and Prevention.

USDA officials said they would post genetic sequences and other information about the new form of the virus to a public repository later this week. Scientists said that would be key to understanding whether the spillover was a recent event or whether the virus has been circulating, perhaps widely, for longer.

91裸聊视频淚f this turns out to have been something that crossed into cattle a couple months ago, a couple months is a long time not to detect it,91裸聊视频� said Michael Worobey, an evolutionary biologist at the University of Arizona who has studied the H5N1 virus in cattle.

He added that it91裸聊视频檚 important for federal officials to share promptly information about a virus that has the potential to trigger a pandemic that could 91裸聊视频渕ake COVID seem like a walk in the park.91裸聊视频�

91裸聊视频淚t91裸聊视频檚 a vital part of national security, global security, the well-being of people, of animals and of businesses in the U.S.,91裸聊视频� Worobey added.

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The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute91裸聊视频檚 Science and Educational Media Group and the Robert Wood Johnson Foundation. The AP is solely responsible for all content.

Jonel Aleccia, The Associated Press