(C) Daily Kos
This story was originally published by Daily Kos and is unaltered.
. . . . . . . . . .
Infectious Updates 3-26-25 [1]
['This Content Is Not Subject To Review Daily Kos Staff Prior To Publication.']
Date: 2025-03-26
WASHINGTON DC reports a measles case was on a train on March 19. The risk specifics are: Northeast Region 175 Train southbound between 7:15 pm and 1:30 am; Amtrak Concourse Union Station, 50 Massachusetts Ave NE from 11 pm to 1:30 am; and on March 22, MedStar Urgent Care Adams Morgan, 1805 Columbia Rd NW, Washington DC. NBC
The Texas outbreak is up to 327 cases. New Mexico’s case count stands at 43. Oklahoma has 9, Kansas has 10, Tennessee just found one. Cases are up over 5-fold in the Americas
Two more types of ticks have been implicated in causing alpha-gal syndrome, the allergy to all mammal products that can last a year or more.
Not just lone star, but deer ticks and western black-legged ticks
An antivax group tied to RFK Jr put up a fake CDC website promoting their falsehoods, but were forced to take it down. Somebody sue their asses!CIDRAP
Following the recent detection highly pathogenic H7N9 avian flu at a Mississippi broiler farm, APHIS yesterday provided more details. It said some North American low pathogenic H7 viruses that it has detected as part of its wild bird surveillance are closely related to the highly pathogenic H7N9 virus, indicating a recent spillover from a low-pathogenic wild bird virus.
The group said it closely monitors the low pathogenic H5 and H7 subtypes, because they can mutate into highly pathogenic versions in poultry species such as chickens and turkeys.
Also, the group confirmed three more H5N1 detections in dairy cattle, all from Idaho, bringing the number of affected herds to 989 across 17 states. Though the pace of outbreaks has slowed nationally, Idaho has now reported six outbreaks since the end of February. (joy. I love my state.)
The infection in an Ohio poultry culler in February was of the D1.3 genotype. This is the first human illness of this genotype, previous cases have been D1.1 from poultry, or B3.13 from cattle. CIDRAP
A dairy herd in Minnesota tested positive...again. It was previously positive in July 2024 and released from quarantine in September. Flagged by milk surveillance
The UK reports H5N1 in a sheep, on a farm that was experiencing a poultry outbreak. The UK has the D1.2 genotype, in multiple poultry outbreaks
Cambodia reports its third H5N1 death this year. A 3-year old boy. All three cases in Cambodia this year have been fatal. They had a large increase in cases from the end of 2023, some involving a reassortment of the old 2.3.2.1c clade that has been circulating there for years with the 2.3.4.4b clade that has spread globally, including the US.
And this probably calls for a little lesson on flu classification.
BASIC GERMINOLOGY
Influenza comes in four basic species, A, B, C, and D. A comes from aquatic birds and frequently jumps into other species, it is sort of a generalist. B and C are human flus. They can occasionally infect a few other species but don’t circulate widely in them. C is very mild or even asymptomatic, and rarely reported. D is found in cattle and pigs. It can infect humans but usually does not cause illness.
B is divided into two lineages, Victoria and Yamagata. However, Yamagata may be extinct because of Covid pandemic measures. It has not been seen since 2021. The lineages are divided into clades, similar to A, as below. C has six lineages.
Flu A causes most of the seasonal flu, with B the runner-up.
This week: Of viruses tested at public health labs, 93.7% were influenza A and 6.3% were influenza B. Of subtyped influenza A viruses, 57% were the 2009 H1N1 strain and 43% were H3N2.
A typical seasonal vaccine contains the most recent clade of H1N1, H3N2, and two clades of B.
A is where the terminology gets lively. A is divided into subtypes according to the two surface proteins, hemagglutinin and neuraminidase. H and N. H is the lockpick that gets the virus into cells, and N is the cleaver that breaks them off of the cells after reproduction. All flu viruses use the sialic acid receptor on the cell membrane.
There are 16 possible H and 11 possible N forms (and two more of H found only in bats), so the possibilities are abundant even before mutations get going. Almost all possible combinations have been found in wild birds. Subtypes such as H1N1, H3N2 (both seasonal flus), H5N1 and H7N9 (both avian flus) are familiar. But of avian flus currently in circulation there are also H5N2, H5N5, H5N9, etc etc.
Then the subtypes are labeled according to their genetic lineages, called clades, with strings of numbers and letters such as 2.3.4.4b, the clade currently circulating in the US and Europe. The clades divide into genotypes, such as D.1.1, D.1.2, D.1.3, B.3.13, and at this point your eyes are probably glazing over. But all this information is supplied each time a sample is sequenced, along with the species sampled, the date, and location the sample was taken. This is how we trace the family trees and look for risky mutations.
Flu A has the highest rate of antigenic drift, which is why it evades previous immunity so easily, and why we get yearly shots. It is also highly susceptible to reassortment with other clades and other subtypes. Reassortment only takes place within the species (A does not reassort with B or C). Reassortment of an avian flu with a human flu is what keeps epidemiologists up at night.
more than you ever wanted to know about flu
.
[END]
---
[1] Url:
https://www.dailykos.com/stories/2025/3/26/2308253/-Infectious-Updates-3-26-25?pm_campaign=front_page&pm_source=more_community&pm_medium=web
Published and (C) by Daily Kos
Content appears here under this condition or license: Site content may be used for any purpose without permission unless otherwise specified.
via Magical.Fish Gopher News Feeds:
gopher://magical.fish/1/feeds/news/dailykos/
