Post Reply - H5N1/flu (other types)

Late on Saturday we learned that Canada had identified their first locally acquired human infection with HPAI H5 in a teenager from the Fraser Valley region.  The patient was reported to be hospitalized in the B.C. Children's Hospital, and was in intensive care. 

Today the B.C. provincial health officer - Dr. Bonnie Henry - held a lengthy news conference, and fielded questions from reporters, on the condition of this teenager, and their investigation. 

Unlike the 45+ American cases who have reported mild illness, this case is listed in critical condition and is suffering from ARDS (Acute Respiratory Distress Syndrome).  The patient - reportedly a healthy teenager - fell ill on November 2nd, with symptoms of conjunctivitis, fever and cough and was seen at a local emergency room, and sent home.

Over the next few days the patient's condition worsen, and they were admitted to B.C.'s Children's Hospital on Friday night (Nov 8th), and a presumptive test for H5 influenza came back on Saturday.  The patient was given antivirals and admitted to the I.C.U.

B.C. health officials have contacted 35-40 close contacts, and have offered them antivirals and will follow up with them for 10 days.  So far, none have shown signs of illness. 

While the investigation is ongoing, so far they've been unable to determine how this teenager was exposed.  The patient did not live on, or visit, a farm or have contact with poultry, or wild birds.  Nor did any of their known contacts. 

The patient did have contact with dogs, cats, and a reptile, but none have tested positive for influenza.  One of the dogs was reportedly symptomatic, but follow up testing has turned up nothing of value. 

While they intend to keep looking for a plausible source - as we saw with the Missouri case last August - answers may never be found. 

Complete sub-typing, and genetic sequencing will take a few days.  For now, H5N1 is strongly suspected, but earlier today WOAH reported at least one outbreak of HPAI H5N2 in a B.C. poultry farm. 

The entire press conference (about 40 minutes) is worth watching. 

While Dr. Henry continues to call this a rare event, it is obvious she takes this seriously, and she warns people to avoid contact with wild birds or sick animals, and to keep their pets away from possible exposures. 

One of the big concerns that Dr. Henry addressed is H5N1's historical disproportional impact on children, adolescents, and younger adults.  This is a topic we've addressed often, most recently last week in Preprint: Immune History Shapes Human Antibody Responses to H5N1 Influenza viruses.

While many have been reassured by the mild presentation of H5N1 in the United States over the past 6 months, this is a reminder that an H5 infection isn't always benign, and that we need to take this threat seriously.