The Washington State Department of Health (DOH) has confirmed the first-ever case of the H5N5 strain of avian influenza in a human, marking the country’s first human bird flu diagnosis since February. A resident of Grays Harbor County, an older adult with underlying health conditions, is hospitalized after exposure to both domestic poultry and wild birds.
Additional testing shows the virus to be H5N5, an avian influenza virus that has previously been reported in animals but never before in humans. Domestic poultry and wild birds are considered the most likely sources of the virus exposure, though the health investigation is ongoing. Public health experts have not found any increased risk to the public to date, according to the press release.
However, the Centers for Disease Control and Prevention (CDC) and DOH currently consider the risk to the public from avian influenza to be low. The DOH urges poultry owners, wildlife handlers, and others who have contact with animals to exercise caution, including avoiding contact with sick or dead birds, using appropriate protective equipment, and reporting sick wildlife or domestic animals to the Washington State Department of Agriculture (WSDA).
The release also emphasizes that while the seasonal flu vaccine does not prevent bird flu infections, it is important because ‘infection with both viruses could result in the emergence of an avian influenza virus that is more easily transmitted from person to person.’ Previously this year, the CDC declared the bird flu emergency officially over, stating the emergency response to H5N1 bird flu was ‘deactivated’ July 2 due to declining animal infections and no human cases since February.
The H5N5 virus is a close cousin of H5N1, with both originating from birds and sharing part of their genetic code. However, H5N5 has a different ‘end piece’ of its structure that changes how it behaves. While H5N1 has caused human illness and even deaths for years, H5N5 has mostly been limited to birds until now, according to health officials.