25 August 2011

Harvesting the blood of horseshoe crabs

One may wonder why the horseshoe crab is sensitive to endotoxin and, furthermore, how does the crab benefit from this phenomenon? As we know, seawater is a virtual "bacterial soup". Typical near-shore areas that form the prime habitat of the horseshoe crab can easily contain over one billion Gram-negative bacteria per milliliter of seawater. Thus, the horseshoe crab is constantly threatened with infection. Unlike mammals, including humans, the horseshoe crab lacks an immune system; it cannot develop antibodies to fight infection. However, the horseshoe crab does contain a number of compounds that will bind to and inactivate bacteria, fungi, and viruses. The components of LAL are part of this primitive "immune" system. The components in LAL, for example, not only bind and inactivate bacterial endotoxin, but the clot formed as a result of activation by endotoxin provides wound control by preventing bleeding and forming a physical barrier against additional bacterial entry and infection. It is one of the marvels of evolution that the horseshoe crab uses endotoxin as a signal for wound occurrence and as an extremely effective defense against infection.
Photo via Fresh Photons, but to read about this, I recommend the Horseshoecrab.org website.

Addendum:  A related story in the Washington Post in May 2012 reports at least an apparent temporary recovery in crab numbers.

17 comments:

  1. Thanks for the read, I recently watched a great documentary about horseshoe crabs and they mentioned and showed how they harvested blood from them.

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  2. As I was reading the article, I had a sudden fantasy flash concerning UFO abduction experiences, in which humans play a role similar to the crabs when they're taken aboard the alien spaceships and subjected to what they describe as strange medical procedures. The aliens are actually siphoning off some substance from the humans that are useful in the alients' medical system.

    Just a fantasy, folks!

    --Swift Loris

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  3. The "Matrix" for crabs. I imagine there is a horseshoe crab "The One" somewhere in a computer fighting to freedom.

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  4. I went to take a bite of toast just as I read that title...lol

    Turned out to be much less gross than I thought, very interesting in fact.

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  5. Animal abuse. Someone find PETA and the agency that's going to save the overweight-failed-dance kid.

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  6. Hi, this is absolutely grotesque, somewhere not far away an extraterrestrial is saying, "See I TOLD you they are barbarians, lets eat them!"

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    1. You sound foolish. Do you know how many lives are saved because of a simple blood donation from these crabs. Yeah it isn't voluntary on the crabs part but there is an over 90% survival rate. Also, when the crabs are brought in they are given a bath and barnacles that can weigh them down and hinder mobility are removed.

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  7. Neat-o (the blue color is super intriguing)
    I do find it interesting that in the picture, the tails have been removed, ostensibly in this case the crabs aren't expected to survive.
    I know that the picture is not connected directly to the linked website, which indicates that they make a point of only bleeding them 30% and once a year, trying to ensure that the crabs survive the process. I'd be curious where the differences lie in these practices. That being said, could the crab survive its tail being removed like that? Can it regenerate like other crustaceans?

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  8. I don't think that the tails have been removed... they are just bent under. You can see the tip of the tail on the first one, and searching google images of horseshoe crabs shows that the back portion of the crab does in fact bend that way.

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  9. Do the crabs survive this? Poor things...

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    1. Most do. I have great respect for the crabs.

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  10. that picture makes me sick, I really hate people.

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    1. Me too. People like you especially. There is nothing wrong with a bleeding heart but you first must educate yourself. You should read up on why crabs are even bled to begin with.

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  11. what they fail to mention here is that yes, the crabs are released (relatively unscathed) back into the ocean. this pic is from a recent issue of national geographic, where they elaborate a little more on the process...

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  12. I perform the Endotoxin Assay as part of my job quite frequently and without the priceless donation from these wonderful crabs it would be impossible to do this test as effectively, if at all under regulated conditions. When I perform the Endotoxin test on the phase I experimental Muscular Dystrophy Gene Therapy Injectable that we make, the crabs and I are helping to ensure that these drugs Do No Harm when injected. Even low levels of Endotoxins can cause extreme inflammatory responses in people who are already sick, especially children.So think for a moment, either a very sick child or person can have a chance at finally becoming well and people in developed nations can have safety measures for health care items from eye drops to surgery, or we can ignore the valuable, renewable, and sustainable (if fragile) resource that is the horseshoe crab population and people can simply take a step back in medical development and lifespan. I also have great respect for the Horseshoe Crab and the contribution made, I'm beyond greatful. I ask that each person viewing the picture and reading the comments (commenting/having commented)just take a moment to find out the why behind any animal related research or scientific production you may hear about, investiators don't use animals fivolously this day and age, only when it is just so beneficial to humans or the animal species itself that one can't justify NOT performing the testing are animals used.

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  13. I completely understand why the crabs are bled. I've read up on it thanks to your blog initiating my interest. However, I am still disturbed by this picture. I find it really repulsive that we are bleeding these animals; albeit, we are saving lives.

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  14. I agree, the picture is disturbing. I will postpone my vegetarian lunch !

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