Tuesday, July 28, 2009

Leech Invasion in Atsugi Japan!!!!

I love the dramatic music.

The Eyes Have it!!!

As an undergraduate student taking Sherwin Desser's JZM252 parasitology course, I was fascinated by the nummber of "worm-in-the-eye" stories with which he regaled us. Loa loa, Onchocerca, Alaria, bot fly larvae, Toxocara (like Baylisascaris procyonis featured in an episode of House)... all potential eye parasites... ugh.
     I have often shown the image at right in public presentations about leeches. If you look closely you can see a Dinobdella ferox peeking out from behind someone's lower upper eyelid and it's back sucker holding onto the eyeball itself (the eye is upside down). This was sent to Gene Burreson by a physician in India many years ago, and it never fails to first confuse, and then disgust, a lunch-time scientific audience!
     The tribulations of people with leeches in their eyes continues. In regions of the world where the terrestrial leeches abound, like Australia and in the wet forests of Madagascar, leeches in the eyes and ears is all too common. Getting aquatic leeches in an eye, while less common, is perhaps more terrifying in light of the larger size of these "medicinal" leeches.
     The Australian story is remarkable for this misperception: "Dr Fogg says tweezers were not an option as simply pulling the leech off could leave its head lodged in the eyeball, leading to infection." Even if leeches had a head, which they do not, for this to be true, the head would have to embed, which it does not since the leech would be unable to suck blood without the seal it makes with its oral sucker.
     We might have Hollywood to blame for this. In The African Queen, Humphry Bogart's character Allnut (a Canadian, I might add), when he emerges from a swamp covered in leeches, declares to Rose (Katharine Hepburn), "No, no, don't touch 'em, don't! Salt, Rosie! ... You pull 'em off but their heads stay in! Poison the blood! Get the salt... If there's anything in the world I hate, it's leeches. Oooh, the filthy little devils."
     If you do get a leech in your eye, salt water will get it out. It will have to be saltier than your tears, so it's likely to sting, and you'll want to flush your eyeball with water afterwards.
     Every photograph of a leech in an eye is one where someone ran for a camera first instead of getting the thing out!

Thursday, July 23, 2009

Marshal Brain - HowStuff(doesn't)Works

Marshall Brain, creator of HowStuffWorks (now a subsidiary of Discovery), which purports to be a clearing house of accurate technological information, badly mangles the truth about leeches in two podcasts: one on what is a medical [sic] leech and the other on how to remove a leech. In these uncited, apparently non-fact-checked articles (none of the leech biologists I know got a call), beyond the preposterous assertion that leeches look like slugs, Mr. Brain claims:
1) that leeches merely double in size when they feed (they can increase 5 times their weight or more).
2) that leeches raised in captivity are "sterile to a certain degree" (all leeches, wild or farm raised harbour Aeromonas in their crop; a course of antibiotics is recommended during post-operative leech therapy)
3) that they quickly attach and start feeding (far from true, especially in North America)
4) that leeches hold on with rows of tiny teeth (they hold on with their suckers, the teeth, far too small for holding onto anything, and which do not meet in any kind of bite, are used only for making incisions)
5) that removal of leeches requires one "to rip the teeth away from your skin" (in fact all that is needed is to gently break the suction seal made by the oral sucker at the smaller end of the leech, once that seal is broken, the leech cannot hold on and can be readily removed by detaching the posterior sucker)
6) that is will not hurt "because the leech has injected a numbing agent" (see my previous post about this unsubstantiated myth)

This is all timely in light of Carl Zimmer taking to task George Will and the Washington Post for failure to fact check on science. Alas, some science writers too fail to fact check. Please note that Discover Magazine where Carl is a columnist has no relationship with Discovery Communications where Brain blogs about "stuff", like medical medicinal leeches.

Tuesday, July 14, 2009

Injury in Iowa - Leeches score another win.

When Eric Poore looked at his finger, there wasn’t much left. Wedding ring smashed, skin, muscle and blood vessels stripped away... nothing but bare bone and the tendons holding the mangled mass together. Paramedics snipped off Eric’s gold wedding band and rushed him to the hospital. Fully four trauma centers declined to treat Poore’s poor finger until Greg Yanish rushed to fix it some hours later. Yanish describes the blood flow in a delicately reattached finger “like the drain in the bathtub is slow, but the faucet is on full blast”. Once more, leeches to the rescue! Application of several (prob. H. verbana) to the reconstructed finger both immediately and over several days and it looks like Eric Poore will get to keep his finger. (As an aside... my EMT friends remind me this is an excellent argument against titanium wedding bands... can’t be snipped off). Here's the full article from the Des Moines Register.