�鶹Ů��

Spikes of influenza A virus seen in wastewater samples from 59 sewer systems across 18 different states this spring may point to the spread of the H5N1 avian influenza virus that is currently infecting dairy cattle, a new study suggests. (Goodman, 4/30)

The U.S. Department of Agriculture will test ground beef for bird flu particles, though officials said Tuesday they’re confident the nation’s meat supply is safe. Bird flu has been found in nearly three-dozen dairy herds across nine states. The new testing is the latest effort by the USDA to track and understand how the virus is spreading among livestock. Two studies will test if particles of the bird flu virus, called Type A H5N1, is found in beef for sale in the states where dairy cows have tested positive or in the muscles of dairy cows sent to slaughter. A third will test how cooking meat at different temperatures affects the virus using a bird flu surrogate. (Shastri, 4/30)

There is a risk that the H5N1 bird flu virus, present in many wild birds, may infect cows in countries beyond the United States as they migrate, a World Health Organization official said on Tuesday. "With the virus carried around the world by migratory birds, certainly there is a risk for cows in other countries to be getting infected," Wenqing Zhang, head of WHO's Global Influenza Programme, said at a news briefing in Geneva. (4/30)

The fact that infections so far appear to be limited to lactating dairy cows, and that the members of a herd that are the biggest milk producers — which are also the animals that stay on milking machines the longest — are the ones most heavily impacted by the disease. “There’s still a lot that’s unknown, but what we’re seeing right now is not a respiratory disease by and large; it’s a mastitic disease,” said Jared Taylor, a professor of veterinary pathobiology at Oklahoma State University. For now, that’s somewhat reassuring, because it means that increased attention to sterilization and disinfection during milking should make a dent in the virus’s further spread. ... Taylor noted another worry: H5N1, which is notorious for its ability to evolve, is being given a huge opportunity to adapt to bovine hosts. “The concern is if it becomes effective as a respiratory pathogen in cattle, it’s more likely to become effective as a respiratory pathogen in humans,” he said.

The ongoing outbreak of H5N1 avian flu virus looks a lot like a public-health problem that the United States should be well prepared for. Although this version of flu is relatively new to the world, scientists have been tracking H5N1 for almost 30 years. Researchers know the basics of how flu spreads and who tends to be most at risk. They have experience with other flus that have jumped into us from animals. The U.S. also has antivirals and vaccines that should have at least some efficacy against this pathogen. (Wu, 4/30)