Bird flu in cows spread only through mammary tissue, not respiration, officials say

The U.S. Department of Agriculture said Tuesday that the strain of bird flu currently circulating among dairy cattle appears to be only transmissible via mammary glands, or udders, rather than respiratory droplets, a finding that gives officials greater optimism about managing the risks facing dairy workers.

This finding could have significant implications for the spread of bird flu from dairy cattle to humans, with dairy workers being most at risk. So far, three people in the United States have confirmed cases of bird flu: One dairy worker in Texas and two in Michigan. 

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