The Washington State Department of Health has confirmed the first-ever case of the rare H5N5 avian influenza strain in the United States, with a resident of Grays Harbor County hospitalized due to infection. The patient, an older adult with underlying health conditions, has been reported to have exhibited influenza-like symptoms since early November, following exposure to a mixed flock of domestic poultry at home that had contact with wild birds. The case not only marks the first human bird flu diagnosis in the U.S. since February but also highlights the growing concern surrounding avian influenza in the region.
Health officials have emphasized that the transmission of avian influenza between humans remains extremely rare and has never been documented in the U.S. However, the recent case underscores the importance of monitoring and controlling the spread of the virus, as it is considered a close relative of the H5N1 strain, which has caused human illness and deaths in the past. Public health authorities have not identified any increased risk to the general public at this time, but they have urged poultry owners, wildlife handlers, and individuals with close contact with animals to exercise caution. This includes avoiding contact with sick or dead birds, using appropriate protective equipment, and reporting any suspicious activity to the Washington State Department of Agriculture.
The Washington Department of Health also highlighted that while the seasonal flu vaccine does not prevent bird flu infections, it plays a critical role in reducing the risk of co-infection with both viruses. Such co-infections could potentially lead to the emergence of a more transmissible form of the avian influenza virus, which could pose a greater threat to public health. The Centers for Disease Control and Prevention and the Washington Department of Health currently consider the risk to the public from avian influenza to be low, although they continue to monitor the situation closely. The case also comes as the CDC has declared the bird flu emergency officially over, noting a decline in animal infections and the absence of human cases since February. However, the emergence of H5N5 highlights the ongoing risk of new strains developing in wild and domestic bird populations.
Experts warn that while H5N1 has been responsible for several human cases and deaths in recent years, the H5N5 strain has primarily affected birds until now. The genetic differences between these strains, particularly the variation in the ‘end piece’ of their structure, are believed to influence their behavior and transmissibility. The case in Washington, though rare, serves as a reminder of the need for vigilance and continued monitoring of avian influenza outbreaks, especially in regions where there is close interaction between humans and bird populations. The Department of Health’s advisory calls for heightened awareness among those working with poultry and wildlife, emphasizing the importance of preventive measures in mitigating the spread of the virus.