An extensive, multi-agency public-health investigation into an avian influenza case involving a B.C. teenager has identified no additional cases nor evidence of human-to-human transmission.

The goals of the investigation were to identify any contacts who may have had exposure to the teenager, determine the source of exposure, and ensure that there was no risk of new infections from either the teenager or animal sources. The investigation also included testing of household pets, birds and other animals from nearby premises, and environmental (soil, water) testing.

To date, all tests on humans, animals and environmental samples related to this investigation have been negative for influenza H5. While it is reassuring that no further cases have been identified, officials have also not been able to definitively identify the source of the young person’s infection.

The investigation has determined the teenager was infected with the same strain of influenza H5N1 currently circulating in wild birds and poultry in B.C. (Clade 2.3.4.4b, Genotype D1.1). Advanced testing at the BC Centre for Disease Control (BCCDC) Public Health Laboratory determined the whole genome sequence of the virus most closely matches that of wild birds found in the Fraser Valley area in October and was not directly related to outbreaks at poultry farms in B.C.

“Our thoughts continue to be with this young person as they remain in critical condition, and their family,” said Dr. Bonnie Henry, B.C.’s provincial health officer. “I am confident in the extensive public health investigation that was led by the Fraser Health team in partnership with the BCCDC Public Health Laboratory, our partners at BC Children’s Hospital and the chief veterinary officer. Though we have not been able to determine definitively the source of exposure, we were able to rule out many potential risks and ensure there are no further cases related to this young person.”

While this was the first case of H5N1 in a person in B.C. and the first acquired in Canada, there have been a small number of human cases in the U.S. this year, including one reported in a child in California last week.

Health, animal and environmental partners across B.C. have also been working together and with the Canadian Food Inspection Agency and other national and U.S. partners to respond to the increased detections of H5N1 avian influenza in poultry farms and wild birds in the province since early October.