Health investigators in Canada have recently concluded their investigation into the H5N1 bird flu infection involving a teenager in British Columbia. The investigation, however, was not able to identify the source of the infection.
In a press release, B.C.'s health officer Dr. Bonnie Henry said they have conducted an exhaustive search and could not find the actual source of the teen's bird flu infection. They added that their investigation included testing health workers, family members, other close contacts, and all animals related to the case. All the tests came back negative, which Henry said meant they had ruled out additional cases of human-to-human transmission.
"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," Henry said in a statement.
What Did the Investigation Find?
Despite failing to identify the actual source, the investigation may have found clues. Specifically, Henry said a whole-genome sequencing found that the bird flu virus in the B.C. teen belonged to the D1.1 genotype, which is closely related to those found in wild birds in the Fraser Valley area in October.
It is important to note that health officials did not find the D1.1 genotype to be directly tied to recent bird flu outbreaks at poultry farms in the area.
While the investigation has concluded, B.C. health officials are still conducting serology testing of patient contacts as well as further observations to determine if there are any mutations that occurred over the course of the infection.
Experts Say the Findings Point to 'Red Flags'
The teen's bird flu infection is not the only one with no known exposure to date. Last week, a child in California also tested positive for the H5N1 avian flu, which followed a third infection in Missouri in September. For both cases, the origins of the infection are still unknown.
This could be alarming, per infectious disease physician Dr. Abraar Karan. Speaking to Salon, Karan said the fact that health officials could not identify the source "raises a lot of red flags." He also noted that the more bird flu spreads between animals, the more chance it has to evolve and mutate to a version that could make it more transmissible between humans---much like COVID-19.
As of writing, 675 dairy herds have been infected with avian flu in 15 states. More than 110 million poultry have been affected by the outbreaks across 49 states, according to the Centers for Disease Control and Prevention.
