A British Columbia teenager who tested positive for avian flu has been removed from supplemental oxygen and is no longer contagious, according to a letter to the editor of The New England Journal of Medicine signed by Canadian health officials.
Letter, Jo It was published on Tuesday and provides a summary and timeline of the case, signed by doctors from the BC Center for Disease Control, BC Children's Hospital, the Public Health Agency of Canada and BC's Ministry of Agriculture.
The patient was a 13-year-old girl who went to a BC emergency room on November 4 with fever and conjunctivitis in the eye.
The teenager, who was said to have a history of mild asthma and a high body mass index, was initially discharged without treatment, but developed coughing, vomiting and diarrhea on November 7 before returning to respiratory problems.
The report said the girl was transferred the next day to the British Columbia Children's Hospital's pediatric intensive care unit for treatment, which included temporary tracheal intubation.
B.C.'s top doctor says they still don't know how the strain of avian flu got the teenager sick. The update comes as another case has been identified in a child in California. As Michel Ghousoub reports, officials stress that the risk of transmission to humans is low.
Additional information posted on the journal's website states that the patient was no longer considered infectious on November 29 and did not require supplemental oxygen until December 18.
It notes that both the girl and her family agreed to the release of further details on her case and that to date the source of her H5N1 exposure has not yet been determined.
It said there were no secondary cases of transmission of the virus at the girl's home or hospital.
The teenager's infection, which was announced in November, was the first human case of H5N1 avian flu in Canada. The Ministry of Health said that the Kishore Fraser Health Region includes Vancouver's eastern and southern suburbs and the Fraser Valley.
BC's commercial poultry sector has been damaged by avian flu outbreaks in recent years. The most recent figures posted on the Canadian Food Inspection Agency's website say more than 8.5 million birds have been “affected” in the province since spring 2022.
Most of the outbreaks reported in the province in recent months have occurred in the Fraser Valley, located within the Fraser Health Region.
Dr. Maria van Kerkhove, director of epidemiology and pandemic preparedness at the World Health Organization, is calling for increased surveillance globally of animal populations considered most susceptible to H5N1, including wild birds, poultry, pigs and cattle.
The investigation into the case of a teenager with H5 avian flu in B.C. included testing of pets, birds and other animals from nearby premises, as well as environmental testing of soil and water, the province said.
It concluded that the strain the teenager contracted was similar to the strain found in wild birds in the Fraser Valley region in October and was not directly related to the outbreak on poultry farms in B.C.
'terrible virus'
A letter to The New England Journal of Medicine states that the H5N1 virus can cause severe human illness.
“The evidence for changes in (protein structures) that can enhance binding to human airway receptors is alarming,” the paper concludes.
A domestic cat has died in the United States after eating raw pet food and contracting H5N1 bird flu. Epidemiologist Dr. Christopher Labos tells CBC News that the risk of any domestic animal contracting avian flu is still low, but the easier it is for it to infect different types of animals, 'ultimately the easier it will be for the virus. infects humans.'
Toronto General Hospital infectious disease specialist Dr. Isaac Bogoch said the letter and its symptoms are consistent with other reports of human cases of avian influenza over the past two decades.
“If you look at how serious this infection was, I think it's pretty fair to say it's a terrible virus,” he told CBC News.
“And also, for lack of a better word, a very strong host response to this virus and a significant inflammatory response.”
Bogoch said the virus is not yet easily transmitted from person to person, but urged authorities to exercise caution.
“We have to make sure that there are as few mammals as possible from this virus,” he said. “So we don't give it a chance to mutate so that it's easily transmitted between people.”
