Swine flew
Posted on 04/27/2009 10:02:54 AM PDT by Ernest_at_the_Beach
Avian flu and SARS rudely awoke the world to the possibility of a new pandemic. Could a seemingly more mundane bug now put the world to the test?
The swine flu virus that may have killed more than 80 people in Mexico and appears to have sickened hundreds more is still a mystery contagion. But this much is known: The virus is unusually made up of genetic material from avian, pig and human viruses; it can transmit from person to person; and in many people, it only triggers mild symptoms seen in garden-variety influenza.
The current virus is mainly sickening the young and the healthy, yet such bugs are notorious for their ability to evolve. "We are too early in our investigations to be able to address the lethality of the virus," said Keiji Fukuda, interim assistant director-general at the World Health Organization, said Sunday. "Properties of flu viruses can change -- they can go from mild to being more severe and can move from being more severe to less."
The WHO, a United Nations agency based in Geneva, said it may have been harder to detect the initial cases in Mexico because the outbreak started during flu season. But when Mexican officials noticed an increase in cases of pneumonia, including serious pneumonia, they launched an investigation and had the virus tested in labs in order to determine the actual strain.
(Excerpt) Read more at online.wsj.com ...
The 1918 flu also attacked young healthy people. It was thought that their robust immune response (due to their age) caused the seriousness of the illness.
Suspected Case In Chicago
Doctors at Northwestern Memorial Hospital are waiting for test results to see if a patient in his 30s has swine flu.
Dr. John Flaherty is the associate chief of infectious diseases at Northwestern University-Feinberg School of Medicine.
“This is somebody that returned from Mexico and essentially got sick on the plane coming back from Mexico and then came right to our hospital.”
WBBM: And when was that?
“That was Saturday.”
Dr. Flaherty says the man is apparently doing all right - and is at home - taking the anti-flu medicine, Tamiflu.
No, you can see this animation how different viral strains can be generated by subunit reassortment:
http://www.hhmi.org/biointeractive/animations/subunit/sub_frames.htm
Influenza A viruses have 10 genes on eight separate RNA molecules (PB2, PB1, PA, HA, NP, NA, M, and NS). HA, NA, and M specify the structure of proteins that are most medically relevant as targets for antiviral drugs and antibodies (An eleventh recently discovered gene called PB1-F2 sometimes creates a protein but is absent from some influenza virus isolates.) This segmentation of the influenza genome facilitates genetic recombination by segment reassortment in hosts who are infected with two different influenza viruses at the same time.Influenza A virus is the only species in the Influenza A genus of the Ortthomyxoviridae family and are negative sense, single-stranded, segmented RNA-viruses
http://en.wikipedia.org/wiki/H5N1_genetic_structure
and here are the probable origins of the 8 separate segments of the RNA in the influenza virus in Mexico:
PB2 Avian North America
PB1 Human circa 1993
PA Swine Eurasia +/-
HA Swine North America
NP Swine Eurasia +/-
NA Swine Eurasia
MP Swine Eurasia
NS Swine Eurasia +/-
This is from Niman :
http://www.flutrackers.com/forum/showpost.php?p=222759&postcount=19
In order to determine the relationship you compare sequences and determine which type has the highest similarity to the segment that you are checking. This can be done in several ways so there are always some disagreements. In this case the PB2 most likely is from an avian strain, and the one with +/- are not so certain but fairly certain of being of the annotated origin. PB2, PB1 and PA codes for different proteins that are critical components of the viral polymerase, i.e. the enzyme that produces RNA. PB2 influences, among other things, what type of cells that are susceptible for infections. A mutation in the PB2 with Lysine instead of the normal Glutamic acid is believed to confer to avian H5N1 viruses the advantage of efficient growth in the upper and lower respiratory tracts of mammals. I'm not so sure that the Mexican flue is that dangerous, we do not yet know how many that had an infection, it might be 10 000 or 100 000 in Mexico, with 200 dead that would be a mortality of 0.2 - 2%.
What might be disturbing is if it causes cytokine storm and kills a lot of people in the 15 - 45 years range, like the 1918 flu:
The difference between the influenza mortality age distributions of the 1918 epidemic and normal epidemics. Deaths per 100,000 persons in each age group, United States, for the interpandemic years 1911–1917 (dashed line) and the pandemic year 1918 (solid line).
SOUTH DAKOTA: The state has two suspected cases of swine flu, State Epidemiologist Lon Kightlinger said Monday. Test samples from those two adult patients are being sent to the state health lab in Pierre for testing and should be available Tuesday, Kightlinger said. The two recently traveled to Mexico. “We are now casting a very wide surveillance net for swine flu in South Dakota,” he said. “This certainly is a fast-changing situation ....
Too soon yet?
I don’t know what to make of it all..
FOCUS: Drug Companies Prepare For Possible Flu Pandemic
Most of those in Mexico are dying of Pneumonia which is what happens after the Influenza wrecks their lungs. From http://www.singtomeohmuse.com/viewtopic.php?t=3232&postdays=0&postorder=asc&start=705
bump read later
That's one for the Metaphor Hall of Fame*
*I know it is a simile but that doesn't have the same ring to it.
While the cases reported so far in the United States seem relatively mild, Besser said, far more will be known about the disease’s transmission traits and severity in a week or two. He said the particular virus at issue had not been seen before, either in the United States nor Mexico.
If you want to do some number crunching here are the swine influenza A (H1N1) sequences http://www.ncbi.nlm.nih.gov/genomes/FLU/SwineFlu.html
I'm not sure if I read about documented cytokine storm in this outbreak, or was it just speculation. The demographic for mortality fits well, unfortunately.
Comment# 25 has a good immunology tutorial. Thanks Ernest!
Hey, Ernest! I thought you some computer geek. :)
Thanks for the info.
I think the demographic is an artifact: the age group is skewed toward younger victims because they were in Mexico on school trips or Spring Break.
Keep in mind also that this is infection, and not mortality (none dead in the US yet, and hopefully there will not be).
I have teenaged grandchildren - what’s the best way to help them if they get this? And for their parents? Does therflu help or hurt?
LOL!
Ahem, I mean that you are EVIL!
I was curious about the cytokine storm. I only have a surface knowledge of cytokines, but like you said this fits the historical data. I hoping my stock of Benadryl and green tea with ginger helps suppress it. I was looking for more info on the anti- inflammatory foods. It would be lovely if someone had some info on suppressing the cytokine storm with nutrition plus drugs.
This thread can answer your questions.
What Gives? Why Is Homeland Security’s Napolitano Giving Swine Flu Briefing? (Video)
http://www.freerepublic.com/focus/f-bloggers/2238661/posts
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