The Washington State Department of Health (DOH) has confirmed the first human case of the rare H5N5 avian influenza strain in the United States, marking the first such diagnosis since February. A resident of Grays Harbor County, described by officials as an older adult with underlying health conditions, is hospitalized after showing influenza-like symptoms in early November. The individual is believed to have been exposed to both domestic poultry and wild birds at their home, as per the DOH.
Public health experts have noted that while the H5N5 virus is primarily found in birds, this case marks the first in humans. Officials emphasize that the risk to the general population remains low, as avian influenza transmission between humans is extremely rare and has never been documented in the U.S. The Centers for Disease Control and Prevention (CDC) and DOH currently consider the risk to the public from avian influenza to be low, though they are closely monitoring the situation.
The DOH has urged poultry owners, wildlife handlers, and individuals with contact with animals to exercise caution. Recommendations include avoiding contact with sick or dead birds, using appropriate protective equipment, and reporting any sick wildlife or domestic animals to the Washington State Department of Agriculture (WSDA). The health department also highlighted that while the seasonal flu vaccine does not prevent bird flu infections, it is still recommended to help prevent the emergence of more transmissible variants of the virus.
Health officials are continuing to investigate the source of the infection, which is believed to be linked to the individual’s mixed backyard flock of domestic poultry that had exposure to wild birds. Although the case is isolated, it underscores the importance of vigilance in monitoring emerging strains of avian influenza, which could have significant implications for both animal and human health.
The CDC had previously declared the bird flu emergency officially over, citing a decline in animal infections and the absence of human cases since February. However, the ongoing case serves as a reminder that the threat of avian influenza remains, and public health authorities are maintaining their vigilance to prevent any potential outbreaks.
Experts also note that while H5N5 is a close relative of the H5N1 strain that has caused human illness and even deaths in the past, the H5N5 virus has primarily affected birds until now. The genetic differences between the two strains, particularly in the virus’s structure, may influence its behavior and potential for transmission to humans.
Despite the rarity of human transmission, the case underscores the need for ongoing surveillance and preparedness among health officials. As the investigation continues, the DOH is working to provide clarity on the potential risks and further measures to ensure public safety.