Thursday, November 13, 2008

Infection Connection



Are you under the influence? I hope not, but if so, get to bed and get some rest, drink lots of fluids, and next year, you might want to consider getting the flu shot.

That's right, I'm not talking about your over-indulgence in certain alcoholic libations, you party animals, I'm talking about everyone's least favorite winter-time scourge, influenza. Influenza is the Italian word for influence, and it is believed to have gotten its name, long before the causative virus was discovered in 1933, because illness was once thought to be influenced by the stars.

Influenza has been around for thousands of years, but pandemics began to take place with the development of large cities in the 18th and 19th centuries. Human influenza developed as a result of close proximity to animals such as pigs, horses, and chickens, and that is still the case. In general, pandemic flu occurs every 25-30 years. (By the way, the difference between an epidemic and a pandemic is that an epidemic is more confined, e.g., to a daycare center or nursing home; a pandemic occurs over a large geographic area and affects the population at large.) It is widely accepted that there were three influenza pandemics in the 20th century, and the mother of them all was what is known as the Spanish Lady of 1918-19, and that is what I'll focus on here.

The 1918 outbreak is now realized to be one of the most widespread and lethal pandemics in world history in terms of deaths. In the United States, some 550,000 people died...more than the military deaths in both World Wars, Korea, and Vietnam. Combined. In beleaguered cities, social services ground to a halt as police officers, firefighters, telephone operators, and garbage collectors fell ill. Schools were closed and businesses were shuttered as public health officials tried in vain to halt the spread of the disease. Cities had to resort to mass graves, as the number of dead grew too large to accommodate individual graves. When both parents died from the flu, orphan children wandered the streets.

By the time the pandemic ended in 1919, it was originally thought that 40-50 million people had died worldwide. Current estimates are 50-100 million. At that time, influenza was not a reportable disease, and not tracked by public health agencies, so records are spotty. But based on descriptions of various illnesses at that time, and the widespread infection rate (up to 20%), it's certain that tens of millions died.

So what made this strain such a killer? Take a look at this chart of deaths by age group. See the U-shaped curve with the dotted line? That's how influenza normally behaves. It kills more children and the elderly. The 1918 strain affected those groups as well, but also seemed to target the young and healthy, as shown on the graph by the solid line. The virus spread like wildfire through military bases, killing many young men in the prime of their life. After the pandemic ended, the strain of virus seemed to vanish into oblivion, with the same symptoms never occurring again. For many years, the virulence of that particular strain was a mystery. All influenza viruses have the usual virulence factors, such as Hemagglutinin, a protein that causes the viruses to stick to the host cell, and Neuraminidase, an enzyme that aids in allowing a virus to enter the host cell; it also aids in the release of replicated viruses produced in infected cells. If you see the notation H5N1, for example, that is how avian influenza is characterized. But there had to be more there in the 1918 strain than the typical virulence factors.

In the late 1990's, a team of scientists found the body of an Inuit woman, a 1918 influenza victim, buried in a mass grave in Alaska. They found well-preserved viral material in her lungs, and they recovered enough viral RNA that they were able uncover the complete gene sequence of the strain that for decades they thought was gone from history (it is characterized as an H1N1 strain). Using this "reanimated" virus, another team of scientists was able to conduct tests (in BioSafety Level 4 conditions--suits and air hoses--of course) that resulted in the discovery of at least one virulence mechanism: in the host, this strain triggers an immune response that is often called a cytokine storm. Massive amounts of chemicals and disease-fighting cells pour into the lungs, resulting in such an accumulation of cellular material and fluids that the victim literally drowns. A similar mechanism has been found with avian influenza, which fortunately is not easily passed from human to human. For now. There is still much to be discovered about the 1918 strain, but what an amazing start, and a possible clue to how to respond more effectively to current strains.

This is one of the reasons I get a flu shot every year! Now, if such a killer strain emerges again (and in my humble opinion, I believe it will), it will be an unexpected strain that has mutated via antigenic shift. The flu vaccine will not fully protect against such a different strain. But there may be enough protection to keep you from the worst case scenario. (That would be death.) That's one of the reasons influenza is such a nasty and unpredictable bug--it's the mother of multiple mutations. If you get a particular strain of influenza, your body puts up a good fight and triggers an immune response...hey presto, you've got antibodies to that strain and won't get it again. But the virus changes from year to year via antigenic drift. These are subtle changes in the virus's RNA makeup, but they are enough that your body is unable to recognize it as a strain it's encountered before, and thus the antibodies from the previous strain aren't released. Still with me? There is no such thing as a natural immunity to influenza. To a particular strain, yes, but that particular strain isn't going to exist next year...it's going to change its makeup just enough so that your immune response won't be full and immediate.

The flu vaccine isn't 100%, and the production depends upon the trends of the previous year. Scientists and doctors do their best to track various strains and figure out what will be the prevalent strains the following year, and include those in the vaccine. This doesn't always work, and last year, we saw a strain that wasn't included in the vaccine. Some of my work pals got it and were laid low for quite a while. But a flu shot can help protect you, your loved ones, and the community in general. Call your doctor, or your county health department, for more information. The county health department should have low-cost or no-cost options for you.

Stay healthy this year, and may all your influences be good ones!

Sources:

University of Wisconsin-Madison (2007, January 17). Lethal Secret Of 1918 Influenza Virus Uncovered. ScienceDaily. Retrieved November 13, 2008, from http://www.sciencedaily.com­ /releases/2007/01/070117134419.htm

NIH/National Institute of Allergy and Infectious Diseases (2007, July 4). Scientists Describe How 1918 Influenza Virus Sample Was Exhumed In Alaska. ScienceDaily. Retrieved November 13, 2008, from http://www.sciencedaily.com­ /releases/2007/07/070702145610.htm

Nikiforuk, Andrew. The Fourth Horseman. London: Phoenix; 1993

Kolata, Gina. Flu: The Story of the Great Influenza Pandemic of 1918 and the Search for the Virus that Caused It. New York: Farrar, Straus and Giroux; 1999

26 comments:

  1. I got the flu shot about two weeks ago, so I am thinking I either had food poisioning or I did have the flu but only got a mild case of it since I had had the shot. I always get the shot! Working in a hospital operating room I think I need it. Linda

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  2. I get the shot every year and have been a whole lot healthier each winter because of it. Good Advice ! 'On Ya'-ma

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  3. I recieved my flu shot a month ago. Being Asthmatic, my doctor makes sure I know when the shots are avaible. Mark recieved his a few days ago.
    I lost a friend to the flu several years ago. She was in her 70s. The influenze is not something to play around with.
    Hugs, Laini

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  4. Interesting. I didn't know the full history of this disease. I know I need to get off my can and get the shot. With Emphysema it can't hurt to protect myself further.

    I kept thinking you were a might quiet today, looks like it was worth the wait. A well written entry to say the least. (Hugs)Indigo

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  5. Hmm, maybe I will need to resurrect my Pandemic Planning entry for our new readers.

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  6. I always learn so much when I visit Nutwood! I need to find out if I had ny shot- I'm not sure!

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  7. I'm chicken of shots... but I am in contact with a lot of people - shaking hands, exchanging money, etc... I'll think about it.

    I loved this history lesson...

    *Hugs*
    heather

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  8. Beth, Very good information. I hadn't realized why the flu was called influenza. :) Learn something new every day. Mac and I have already gotten our shots, Kim and Kendra will be dealt with by next weekend. I like getting the shot because I also seem to have fewer colds.

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  9. quite honestly, the flu shots where i live are priced out of SOME people's economic ability to pay for it. Nowhere near me is it free. Which is really a shame because some will get it and have to work thru it and infect others.
    Well written entry as usual. XO

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  10. My doctor insists that I have a flu shot annually. I'm at the front of the line. I din't know all the details of the 1918 pandemic; fascinating reading. You have a real knack for making the complex understandable. Thanks.

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  11. This was a very interesting read and I learned alot tonite! I don't get a flu shot, I had one and got so sick I vowed I would never get one again and haven't. I haven't had the flu in years (here I go jinxing myself and will most likely get a horrible case this year!) I wonder if the fact that I am around all kinds of animals all the time has built up my natural immunities. I am around sick people at work all winter but never catch it. I hope you stay well this flu season.

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  12. Hmmm, maybe I should have gotten one, though the one time I did, I became so ill, I vowed never to get it again. My insurance does not cover it.

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  13. I love getting the flu. It feels so dramatic. But since it could kill me, I do get a flu shot.
    But you gotta stay away from those Italian. Sal Monella is another one.
    You is a walking history channel.

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  14. I got mine, thank goodness and now am trying to get hubby to get his.
    I have taken it for years and never had any side effects.

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  15. Your smart makes my brain hurt. ;)~ I'm not a fan of any virus. When I was in school, first learning about viruses, they were explained to me in an... unforgettable way. The teacher told us the virus was like an invader from another country, your white blood cells are the soldiers of your body. The virus (like a creature of the undead or some horror movie equivalent) infects healthy cells and turns them into "one of THEM" (hear the scary thematic background music yet?) Eventually, the white blood cells catch on (hopefully, otherwise, that dying thing comes into play) and a war begins inside your body. The first white blood cell tells the white blood cell next to him what kind of cells to be on the lookout for and chain reaction spreads through them within your body. Eventually, after an asskicking war has occured, all the virus undead have been destroyed and your body goes back to it's normal schedule. Every time I get sick now, I imagine all these little cells communicating to eachother. The entire time I'm sick, I act as a cheerleader for my white blood cells. lol
    Love,
    Jamie

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  16. Hi Beth,
    Wow ... good advice. Thanks.
    Best,
    Marty

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  17. Great entry Beth, a public health warning and a history lesson, all in one. I had no idea the 1918 flu killed so many!

    B. x

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  18. I got mine, as usual. It's required of kidney patients, which is a good thing.

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  19. This certainly was interesting visit to Nutwood !Thank you for this entry.
    Take Care and stay healthy ! (just sayin') !

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  20. Good information here, may have to start getting flu shots because of it.

    BUT, one of the reasons that african american folks are so distrustful of such things, is mention and if you stretch with me, you will see.

    They found in the Inuit woman, a strain of that great flu virus. Fine, you say. BUT, I do believe, and most older black folks do, that the militarization of such virus happens regularly. You only need on 'Tuskeegee Experiment' to convince a group of people the inhumanity of men, esp. in the name of science.

    Hey! YOU prolly should be familiar with Stephen King's book (not the somewhat disappointing mini-series) 'The Stand'! I don't question if that can happen, as I believe that it does.

    Still, I will consider getting a flu shot (yes, I did talk myself out of 'for sure')

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  21. Hack, hack.....achoo~hack, hack........

    Too late......already got it~

    Interesting information though!

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  22. I get a flu shot every year but did not get one until I was probably 65. Interesting article. Lucy

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  23. HiBeth,
    Just got mine! Better late than
    never! Got the flu last year, and
    it was awful. This was very interesting
    and informative. Thanks. Pat

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  24. Only ever had the flu jab once and that was the year i had flu worse than ever before or since.

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  25. We all get our flu shots every year.....With all of us now in health care it is essential...I also have heard of many people bemoaning he fact that they got sick after the shot, I was probably a differnet virus that the one they were innoculated against.....

    Claudia

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  26. This was an interesting history(and science) lesson. My great aunt died of influenza during that era(not sure of the exact date).
    :) Leigh

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