A British Columbia doctor who treated a 13-year-old avian flu patient says the case has made him concerned about the potential for more human H5N1 infections.

While the patient was recently discharged from hospital with her case deemed rare, the two-month ordeal is being examined to better understand the path of avian flu from wild birds and poultry to humans, who get very sick.

Dr. David Goldfarb, a medical microbiologist and pediatric infectious disease physician at B.C. Children鈥檚 Hospital, first saw the young patient on Nov. 8.

She was in respiratory distress, but there was no 鈥渃lear flag鈥� that suggested she was infected with avian flu. Goldfarb sent diagnostic tests to the hospital lab to determine the type of influenza that had sickened the teen. They all came back negative.

Occasionally, he said this happens if the sample is weak with a very small amount of the virus in it.

But it wasn鈥檛 a weak sample. It was actually reasonably strong, he said.

That was the initial red flag. As soon as these results came back, the patient was placed in a negative pressure room and her medical team put on N95 respirators. It鈥檚 standard protocol to add airborne precautions when there鈥檚 reason for concern that a patient could have a novel influenza.

As Goldfarb took a closer look at the case he started to notice symptoms associated with recent cases of avian flu, such as pink eye, and wanted to test his theory as soon as possible.

鈥淚 called my colleague at the B.C. Centre for Disease Control and arranged for urgent testing for the H5N1 test, which is for the avian flu strain. That was done that same day, and we had that result by the evening of the admission to our hospital,鈥� Goldfarb said.

The result was positive. 鈥淎ll of us kind of recognize the significance,鈥� Goldfarb said.

This was the first H5N1 case acquired in Canada.

The teen鈥檚 medical team expanded to dozens of specialists, including clinical microbiologists, infectious disease doctors, respiratory therapists and intensive care nurses. Meanwhile, public health officials in Canada investigated how she got infected, the source of which remains undetermined, and a lead expert on avian flu at the U.S. Centers for Disease Control and Prevention (CDC) was consulted on next steps.

She started an antiviral the day of her diagnosis. The team initiated a combination therapy that added two other antivirals, sourcing one from the U.S., to her treatment.

In respiratory distress, the teen patient was intubated and placed on life support on Nov. 9. Daily plasma exchanges started Nov. 14.

鈥淭his child needed a lot of support, basically the maximum amount of respiratory support that we鈥檙e able to provide in a modern ICU,鈥� Goldfarb said.

This multidisciplinary approach went on for weeks until the patient鈥檚 respiratory condition began to improve. She was taken off of supplementary oxygen on Nov. 22 and extubated the following week.

On Jan. 7, she was discharged from hospital. Her family released a statement asking for privacy as they healed from what they called a traumatic experience.

Goldfarb said he couldn鈥檛 share more about the patient鈥檚 current condition or what her medical care would look like moving forward, but he said that the patient had recovered to the point that she was able to go home.

The B.C. Centre for Disease Control is comparing the genetic features of her avian flu strain with that of a Louisiana patient who died last week. The U.S. patient shared one of the three genetic mutations identified in the Canadian teen, which infectious disease experts have said could make it easier for the virus to spread from person-to-person.

Goldfarb said the shared mutation is associated with binding to human cells better. A virus can鈥檛 live on its own, he explained, 鈥淚t鈥檚 basically an inanimate object. But once it attaches to a host is when it becomes animated and then begins its life cycle 鈥� if a virus is able to bind better, then that means it can then potentially transmit to others.鈥�

With the B.C. patient there was no evidence of human-to-human transmission, which Goldfarb said means the mutation was a dead end in this case.

Still, he said, 鈥淚t was worrisome, because theoretically, if this virus is able to do this and has more opportunities to adapt to humans, there may be a situation where it does become more adept at human-to-human transmission.鈥�

In North America he said we鈥檝e been relatively sheltered from the spread of avian flu until this point. Historically the risk of infection was highest for those travelling to Asia and Africa, but since 2022, the virus has become widespread across Canada through the migration of wild birds.

In the U.S., the CDC has reported 66 cases of H5N1 in humans and one death associated with the infection. They have also detected almost 11,000 wild birds with the virus.

A Canadian Food Inspection Agency dashboard shows more than 3,400 positive samples of avian flu have been confirmed in wildlife in the country.

鈥淲hat鈥檚 different about our current era, is that we are now, for the first time, seeing severe, locally acquired avian influenza. So it is something that will likely, unfortunately, continue to see in North America.鈥�