REUTERS: Scientists tracking the spread of bird flu are increasingly concerned that gaps in surveillance may keep them several steps behind a new pandemic, according to Reuters interviews with more than a dozen leading disease experts.
Many of them have been monitoring the new subtype of H5N1 avian flu in migratory birds since 2020. But the spread of the virus to 129 dairy herds in 12 U.S. states signals a change that could bring it closer to becoming transmissible between humans. Infections also have been found in other mammals, from alpacas to house cats.
“It almost seems like a pandemic unfolding in slow motion,” said Scott Hensley, a professor of microbiology at the University of Pennsylvania. “Right now, the threat is pretty low … but that could change in a heartbeat.”
The earlier the warning of a jump to humans, the sooner global health officials can take steps to protect people by launching vaccine development, wide-scale testing and containment measures.
Federal surveillance of U.S. dairy cows is currently limited to testing herds before they cross state lines. State testing efforts are inconsistent, while testing of people exposed to sick cattle is scant, government health officials and pandemic flu experts told Reuters[…]Dr. Jeanne Marrazzo, director of the U.S. National Institute of Allergy and Infectious Diseases, said surveillance for humans is “very, very limited.”
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Early Surveillance And Detection Are Needed To Adequately Respond
Some pandemics, including COVID-19, arrive with little warning. In the last flu pandemic, caused by H1N1 in 2009, the virus and its predecessors had first spread among animals for several years, Hensley said, but more surveillance would have helped health authorities prepare.
Three people in the U.S. have tested positive for H5N1 avian flu since late March after contact with cows, experiencing mild symptoms. One person in Mexico was infected with a separate H5 strain not previously seen in humans, and with no known exposure to animals. Other cases were reported in India, China and Australia, caused by different strains.
The World Health Organization says H5N1’s risk to humans is low because there is no evidence of human transmission. Some tools are available if that changes, including limited amounts of existing H5N1 vaccine and antiviral medications like Tamiflu. There are mechanisms to launch larger-scale production of tests, treatments and vaccines, if needed, said the U.N. agency’s head of flu, Wenqing Zhang.