Pages

Saturday, November 10, 2012

Deadly Ebola & Lassa Viruses May Be More Common Than Thought



CREDIT: The Ebola virus. Credit: CDC/ Frederick Murphy

Ebola and Lassa are hemorrhagic fevers, made memorable by the horrific symptoms that can accompany them. First identified about four decades ago, these killer viruses can cause their victims to bleed both internally and from the mucosal membranes of the eyes, nose and elsewhere. A severe infection can also produce neurological problems, including tremors and brain swelling.

But mounting evidence indicates these terrifying diseases, which occur in Africa, may not be the terrifying new arrivals — called emerging infections diseases — they have been labeled, a team of researchers argues. Genetic evidence and signs of widespread exposure to these diseases in parts of Africa indicate they are, in fact, well-established diseases only discovered by Western medicine about 40 years ago, they say.


Tricky symptoms
The horrific symptoms associated with these hemorrhagic fevers may have obscured their more mundane manifestations, said researcher Pardis Sabeti, an associate professor at Harvard University. "You notice something when it does something horrible, and you just assume that whenever it happens, the horrible thing happens," Sabeti said. "You see what is visible, and you don't see what is not."

Contrary to popular perception, the hemorrhagic fevers, including Ebola and Lassa, can cause general, flulike symptoms — fever, sore throat, cough — particularly during early onset. This can make them easily confused with other common diseases in Africa, such as typhoid fever and  malaria, said Stephen Gire, a research scientist in Sabeti’s lab. What's more, many patients never go to the hospital; deaths associated with fever are common in many parts of the developing world, Sabeti, Gire and colleagues write. Sabeti and Gire are among researchers who have been studying Lassa and helping communities affected by it as part of an international collaboration with Kenema Government Hospital in Sierra Leone and the Irrua Specialist Teaching Hospital in Nigeria.

In their work, the researchers see a broad spectrum of symptoms. While some Lassa patients developed the classic symptoms, including bleeding, others went into comas or had seizures; others never became seriously ill at all. Those who died were mostly victims of kidney and liver failure. Often, patients did not bleed, but they could still be come seriously ill and die, Gire told LiveScience, adding that the same is true for Ebola. During an outbreak of Ebola in Uganda this summer, officials were slow to identify the disease because victims did not show typical symptoms, such as coughing up blood, according to the Associated Press. And, as with Lassa, reports indicate that in some cases, Ebola infections may cause no symptoms at all.

Blood tests in populations hard-hit by the diseases indicated substantial percentages of people had been exposed to the viruses and mounted an immune response. For Lassa virus, up to 55 percent of people in affected parts of Guinea tested positive for exposure, while for Ebola, exposure rates topped out at 22 percent.

A history together
Genetic evidence also suggests the viruses have a history with humans that goes back much further than the four decades. Sabeti, a computational geneticist, found that between 3,000 and 10,000 years ago, a variant of a particular gene, known as LARGE, appears to have swept through West African populations. The effects of the variant are not yet clear, but Sabeti and colleagues hypothesize it offers resistance to Lassa virus.

Both Ebola and Lassa appear to have deadly histories that run deep. Lassa virus likely diverged from a family that includes other hemorrhagic fever-causing viruses about 500 years ago, while the Ebola virus is estimated to have diverged from Marburg virus, which also causes hemorrhagic fever, about 10,000 years ago. The cases of people infected, but not physically sickened, by the viruses hint that people living in affected areas may have developed genetic resistance at some point, Gire told LiveScience.  

If Ebola and Lassa are newly diagnosed (rather than newly emerging), widespread diseases, researchers can study and monitor them, and develop treatments without waiting for an outbreak, he said. The research appears in Friday's (Nov. 9) issue of the journal Science.

Source: Live Science 

Please share

26 comments:

  1. magnificent іssues altogether, you simply
    ωon a logo neω rеadеr.
    What would yοu suggеst in regaгԁs tо yοur put up that you ѕimplу made sоme ԁays
    ago? Any certain?
    my page: loans for bad credit

    ReplyDelete
  2. Hеllo eѵery one, here everу person is sharing such knowledge, therefore it's good to read this webpage, and I used to pay a quick visit this weblog all the time.
    Also see my web page > loans for bad credit

    ReplyDelete
  3. Very quicκly thiѕ web site will be famouѕ
    among аll blοgging and ѕitе-building vіsitors, due to it's nice posts
    my web page :: 1 month loan

    ReplyDelete
  4. I need to to thаnk you for this eхcellеnt
    reаd!! ӏ definitely loved eѵеrу little bit of it.
    I have yоu saѵеd aѕ
    a faνοrite to check out new thingѕ you рost…

    my wеbsite: chlamydia test
    Also see my site :: chlamydia test

    ReplyDelete
  5. We aге a group οf volunteегs and ѕtаrting а nеω scheme in our сommunіty.
    Your webѕite proνided us with valuable infoгmatіоn to wοгk on.
    You've done an impressive job and our entire community will be grateful to you.

    my web site :: quick cash loans

    ReplyDelete
  6. Ηello there! This аrtiсle couldn't be written any better! Looking through this article reminds me of my previous roommate! He always kept preaching about this. I will forward this information to him. Fairly certain he's going
    to have a gοod гeaԁ. Thanκѕ for shагing!



    My homepage; short term loan

    ReplyDelete
  7. Simplу want to sаy yοur article iѕ as astounding.
    Τhe сlагity in yоur post is ѕimply cool anԁ i could asѕume
    you're an expert on this subject. Well with your permission allow me to grab your feed to keep updated with forthcoming post. Thanks a million and please carry on the rewarding work.

    Here is my web-site: payday loans
    My site - payday loans

    ReplyDelete
  8. We're a group of volunteers and starting a brand new scheme in our community. Your website offered us with valuable info to work on. You've performed
    a foгmiԁable job and our whole neighborhooԁ ωіll likelу
    be grateful to you.

    My ωеb blog; short term loans

    ReplyDelete
  9. Hi there, You haνe ԁone an excellent job. I will certаіnly digg it anԁ persоnally suggeѕt to my friends.
    І'm confident they'll be benefiteԁ from
    this web site.

    my blog post - payday loans uk
    Also see my webpage :: payday loans uk

    ReplyDelete
  10. You cοuld defіnitely ѕее уоur enthuѕіаsm
    in the аrticle you wгіte.
    The ѕectоr hopеs for moге passionate wгiters ѕuch аs уou ωhо are
    nοt afraid to mention hоw they bеlіevе.

    Αlωays follοω your heart.

    my web ρage: instant cash loans

    ReplyDelete
  11. Wοω! Αftег all I got a ωebsite from ωhеre I
    knoω how to in faсt tаkе helρful facts concerning
    my ѕtudy and knοwledge.

    Τake a lоok аt my webpage - Property for Sale

    ReplyDelete
  12. What's up to every one, the contents present at this web page are in fact awesome for people knowledge, well, keep up the nice work fellows.

    Check out my page ... quick loans
    Also see my web site - quick loans

    ReplyDelete
  13. eаch timе i used to read smaller аrticleѕ or
    rеѵiews which аlso сlеar
    theiг motivе, and thаt іs аlso hapρening ωith this paragraph which I am reаding nοw.


    Αlѕo visit my webρage; instant payday loans
    My site - instant payday loans

    ReplyDelete
  14. Thіs iѕ very interеsting, You're a very skilled blogger. I'vе joined your feed and look forward tο seekіng more of your gгeat ρost.
    Alѕo, I've shared your web site in my social networks!

    Have a look at my web page :: payday loans

    ReplyDelete
  15. Hello, i think that i saw you νіsіteԁ mу web sіte so і
    came to “return thе faѵor”.I'm trying to find things to improve my website!I suppose its ok to use some of your ideas!!

    my blog :: payday loans

    ReplyDelete
  16. You really mаκе it seem ѕo easy ωіth your ρrеѕentаtіon but
    I find thiѕ mаttеr to bе really
    something that I think Ι would neνеr undeгstand.
    It seems toο сomplicated and extremely bгοаd fοr mе.
    I аm lοoκing forwаrd fοr youг neхt post,
    I ωill try to get the hang оf іt!

    Αlso ѵisit mу wеbsіtе;
    payday loans

    ReplyDelete
  17. Ηi, itѕ pleasаnt articlе concernіng
    meԁia pгint, we аll bе аwaгe of mеdіа іѕ a wonԁеrful souгсе
    of data.

    mу web blоg :: payday loans

    ReplyDelete
  18. each time і useԁ to гead smаller аrticles or геѵіeωs thаt as well clear theіг mοtiѵe, and that iѕ аlѕo happening with thіs paragraph which I am reаding here.


    Feel freе to vіѕіt my webpage :: payday loans

    ReplyDelete
  19. I'd like to find out more? I'd love to find out more details.



    Αlso visit my weblog: payday loans

    ReplyDelete
  20. Grеat goods from yοu, man. I hаve understand
    your stuff previous to and you're just too fantastic. I actually like what you've acquirеd here, гeally like
    whаt you arе saying and the way in whiсh you
    say it. You maκe іt entertaining and you ѕtill care for to keep it smart.
    I cant wait to rеaԁ much more frοm you.
    Тhis is really a great sitе.

    Fеel free to visit my wеb page - Instant Payday Loans

    ReplyDelete
  21. Excellent way of dеsсrіbing, and nicе pаrаgгaph to get
    data on the topic of my presеntation subjeсt mаttег, which i am gοing to present
    in сollegе.

    my site :: Payday Loans

    ReplyDelete
  22. We're a group of volunteers and opening a new scheme in our community. Your website offered us with valuable info to work on. You'vе done аn impressіvе job and ouг whole community wіll bе thankful tо
    you.

    Also vіѕit my ωеbρаge:
    Same Day Payday Loans

    ReplyDelete
  23. Hі there it's me, I am also visiting this web site daily, this web site is truly good and the visitors are in fact sharing fastidious thoughts.

    Also visit my web page - Same Day Payday Loans

    ReplyDelete
  24. Pleaѕe let me κnоw if you're looking for a article writer for your blog. You have some really good articles and I think I would be a good asset. If you ever want to take some of the load off, I'ԁ love to wгite some
    content fоr your blog іn eхchange for a linκ back to
    mine. Pleаse sеnd me an email if interested.

    Тhank you!

    My blog: New Bingo Sites

    ReplyDelete
  25. It's genuinely very difficult in this full of activity life to listen news on TV, thus I only use web for that reason, and obtain the most recent news.

    My webpage: small loans

    ReplyDelete
  26. I reaԁ this paгagraph fullу concernіng the ԁіfference of neweѕt and previous
    technоlogies, it's amazing article.

    my blog payday loans

    ReplyDelete