Infectious disease experts say the case of bird flu that infected a 13-year-old girl in British Columbia shows worrying signs that the virus could mutate to more easily infect humans. They still note that the therapeutic approach adopted can help to shed light on future cases.
Posted at 10:42 p.m.
In a letter published Tuesday in the New England Journal of MedicineCanadian health officials identified changes in the viral genome sequence in samples taken from the teenager who tested positive for bird flu and was treated in Vancouver.
The case report says the teen was taken to a pediatric intensive care unit with respiratory failure and pneumonia on Nov. 8, endured a long hospital stay and was able to stop his oxygen therapy on December 18.
British Columbia Health officials told The Canadian Press on Thursday that the patient has not been released from the children’s hospital, but is no longer in intensive care. They said they still don’t know how the teen became infected.
A worrying change
According to the report published in the New England Journal of Medicinethe young girl, who suffers from mild asthma, went to the emergency room for the first time on November 4 with a fever and conjunctivitis.
A genomic sequence taken eight days after the onset of his symptoms showed three mutations in the sample, notably in genes that “facilitate the entry of the virus into cells of the human respiratory tract and allow viral replication”, indicates the case study, adding that the evidence of change is worrying.
Doctors took a multi-pronged approach, giving the teenager all three approved antiviral treatments available for bird flu, in addition to intubation and ventilation.
According to Health Canada, there are few reports of human-to-human spread of avian flu, also known as H5N1, in other parts of the world. In most cases, human avian flu infections are acquired after an interaction between a human and an infected bird.
The reason bird flu does not spread easily from person to person is that it has difficulty binding to receptors in humans’ upper respiratory tract, explained Dr.r Brian Conway, medical director of the Vancouver Infectious Diseases Centre.
He noted, however, that “these mutations – the three mutations described in the article – increase the likelihood or ease with which the virus combines with receptors in the human respiratory tract and this would explain why it is infectious for humans.” man: that he bonds more easily. »
Dr Conway said the challenge in drawing conclusions about bird flu is that there are a small number of human cases. The 13-year-old patient was the first human case of H5N1 contracted in Canada. That’s a good thing, but it makes it difficult to identify mutation trends in the virus beyond a single case, he said.
Another change
South of the border, a severe case of avian flu in humans in Louisiana showed the same hemagglutinin gene mutation as the specimen collected in British Columbia, according to a genetic analysis published by the Centers for Disease Control and Prevention. disease prevention last week, “suggesting that these mutations appeared during the clinical course, when the virus replicated in the patient.”
The Dr Jesse Papenburg, a pediatric infectious disease specialist in Montreal, says what is reassuring is that there has been no evidence of human-to-human transmission in the British Columbia and Louisiana cases, and that the Risk to humans remains low, outside of those working in the poultry industry. The case study notes that there have been no secondary cases of transmission of the virus at home or in hospital.
It is important for public health officials and infectious disease specialists to closely monitor changes in the virus that could lead to potential human-to-human transmission.
Dr Jesse Papenburg, specialist in pediatric infectious diseases in Montreal
The Dr Tim Uyeki, chief medical officer of the CDC’s influenza division in the United States, said this was the first patient he knew of who received triple-combination antiviral treatment for the H5N1 virus, which included neuraminidase inhibitors, amantadine and baloxavir.
Dr Uyeki, who was also a co-author of the case study, said the 13-year-old patient’s doctor called him on the day of her admission and they have been in regular contact about it since then.
The patient’s condition subsequently improved, but Dr Uyeki cautioned that this was just a single case study of the experience of one patient, who also received other treatments, such as renal replacement therapy.
He noted, however, that the approach of giving one patient three antiviral drugs may help inform the clinical management of other critically ill patients. The CDC has confirmed 66 human cases of bird flu in the United States, including 37 in California.
Typically, only one medication is prescribed to a patient at a time, but in British Columbia, two more were added due to the exceptional nature and seriousness of this case, said Dr Papenburg based on details included in the study.
“Fortunately, mortality from influenza in children is very rare. It happens and as you can see in this case […] It came as close to death as possible. »
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