Post Reply - H2H-H5N1 spread in US

an underestimate

   https://afludiary.blogspot.com/2024/07/cdc-updates-on-seroprevalence-genetic.html or https://afludiary.blogspot.com/2024/07/cdc-updates-on-seroprevalence-genetic.html ;
In addition to announcing the 5th & 6th human H5 infections from the Weld Colorado poultry outbreak, last night's CDC's weekly avian flu update contained details on a small seroprevalence study looking at dairy workers in Michigan, and partial sequencing of the virus in Colorado. 
-
The CDC also confirms what we first learned about earlier this week GISAID: The Plot Thickens;  that it is the bovine B3.13 genotype that has spilled over into poultry, and then into humans, in Weld County, Colorado. 
Posting the sequence of the influenza virus genome from a positive specimen collected from one patient in Colorado participating in an A(H5N1) infected poultry farm depopulation (A/Colorado/109/2024) to GISAID (EPI_ISL_19263923) and GenBank (PQ032835). CDC sequenced the influenza virus genome, confirming the neuraminidase (the N in the subtype) is an N1 and the virus is a  HPAI A(H5N1) virus from clade 2.3.4.4b. An analysis of the sequence indicates:
This virus is genotype B3.13 clade 2.3.4.4b HPAI A(H5N1) with each individual gene segment closely related to viruses detected in recent poultry outbreaks and infected dairy cattle herds made available from USDA. Among human virus sequences, A/Colorado/109/2024 is most similar to the genome of the human case in Michigan.
-
Overall, the genetic analysis of the HPAI A(H5N1) virus in Colorado supports CDC's conclusion that the human health risk currently remains low.

While there is certainly some heartening news in these reports, it is also fair to say that the goalposts have recently been moved.  

Had anyone dared predict last March - that in 4 months time - we'd have roughly 160 cattle herds infected with H5N1 across 13 states (an underestimate), that we'd be battling large mid-summer outbreaks of H5N1 in commercial poultry, and that we'd have chalked up 10 human cases in the U.S., they'd have been called an alarmist. 

A reminder that we shouldn't confuse `increasingly commonplace' with `normal'. 

DJ, If in a crisis known cases represent 4 to 15 x unknown cases then on top of 10 known human H5N1 infections between 40 and 150 unknown infections may be around.

Next post Oregon twitter info on H5N1 H2H spread there-CDC simply not testing...