Post Reply - A new pandemic

if they do a test at all)

   https://afludiary.blogspot.com/2024/11/cdc-confirms-california-h5n1-infection.html  or https://afludiary.blogspot.com/2024/11/cdc-confirms-california-h5n1-infection.html ;Friday, November 22, 2024
CDC Confirms California H5N1 Infection In A Child - FluView 6 Cases Added This Week
Via an emailed statement (below) the CDC today confirmed the results reported earlier this week (see California Dept Public Health: Investigating Presumed Positive H5 Infection In A Child), including identifying the subtype as H5N1.
Including this most recent case, 55 human cases of H5 bird flu have now been reported in the United States during 2024, with 29 in California.  
While the official CDC count has risen to 55, this does not include 4 cases confirmed by state labs but not by the CDC, nor does it include the 2nd, strongly suspected case in Missouri, or the 8 asymptomatic and/or mild cases retrospectively identified by serological testing.
These detections via serological testing strongly suggest some additional cases have gone unidentified. How many, is unknowable.   
It takes more than a little luck for a community case  - one w ithout known contact with livestock or someone who is known to be infected - to be picked up by surveillance.  Most doctors and walk-in clinics only perform rapid flu tests (if they do a test at all), and that generally does not reveal the subtype, only if it is Influenza A positive or not. 
While there may be a heightened index of suspicion in community with outbreaks of H5N1 in cattle or poultry, in most communities mild or moderate cases can be difficult to detect. The Missouri case was only identified a week after the patient was released from the hospital.
Last year, in UK Novel Flu Surveillance: Quantifying TTD, the HKHSA described some of the challenges in detecting or confirming community spread of H5N1 - even in the UK - until after dozens, or even hundreds, of cases had occurred.

And with seasonal flu on the rise, along side other winter respiratory bugs, it is only going to become more difficult to identify novel infections in the community. 

DJ, It only just begun...