Latest Bird Flu Case Involves Strain Never Before Reported in Humans

A Grays Harbor, Washington, resident, who was hospitalized with influenza symptoms in early November, has been confirmed to have influenza A H5, a type of bird flu, and health official reported on Friday has died. Testing at the UW Medicine Clinical Virology Lab identified the virus as H5N5, making this the first recorded infection with this variant in a person globally. The result was confirmed by the Centers for Disease Control and Prevention (CDC).

The person was an older adult with underlying health conditions. The CDC consider the risk to the public from avian influenza to be low. This marks the first case of bird flu in the U.S. in nine months, and as of January the CDC has confirmed 71 cases in humans and two deaths.

The affected person has a mixed backyard flock of domestic poultry at home that had exposure to wild birds. Domestic poultry or wild birds are the most likely source of virus exposure; however, a public health investigation is ongoing. The Washington State Department of Health is working with the local health department and the Washington State Department of Agriculture to complete exposure and animal health investigations. 

The risk of avian influenza increases in the fall and winter because migratory birds can carry the virus and spread it to domestic animals including commercial poultry farms and backyard flocks.

It is especially important that people who may have exposure to sick birds get a seasonal flu vaccine, Washington health officials said. While the seasonal flu vaccine will not prevent bird flu infection, it reduces the risk of becoming sick with both human and bird flu viruses at the same time. Though unlikely, infection with both viruses could result in the emergence of a bird flu virus that is more easily transmitted from person to person. Seasonal flu vaccine is recommended for everyone six months and older.

Transmission of avian influenza between humans is extremely rare and has never been documented in the U.S. To ensure that human-to-human spread is not occurring, public health officials are contacting anyone who has been in close contact with the patient to monitor for symptoms and provide testing and treatment as needed.