A new form of bird flu has been found in cows in Nevada. This means that the virus can now spread to cows and may pose a risk to people who work with them. Scientists did not know that cows could get this kind of flu before. The virus has infected many herds in different states. It started in birds and then jumped to cows about a year ago, which was a surprise to scientists. Now, it has happened again in a different form. This news was announced by the U.S. Department of Agriculture. They are worried about how the virus could continue to spread.需要进一步了解本文的内容。如果您是时的订阅者，请单击此处登录您的帐户。感谢您的耐心等待。