February 4th, 2008

more zoonosis, Baylisascaris procyonis

The Toxoplasma gondii posts reminded me of this. Rehabber friends have left me forever irrationally paranoid of death by raccoon roundworm.

"Baylisascaris procyonis, a roundworm infection of raccoons, is emerging as an important helminthic zoonosis, principally affecting young children. Raccoons have increasingly become peridomestic animals living in close proximity to human residences. When B. procyonis eggs are ingested by a host other than a raccoon, migration of larvae through tissue, termed larval migrans, ensues. This larval infection can invade the brain and eye, causing severe disease and death. The prevalence of B. procyonis infection in raccoons is often high, and infected animals can shed enormous numbers of eggs in their feces. These eggs can survive in the environment for extended periods of time, and the infectious dose of B. procyonis is relatively low. Therefore, the risk for human exposure and infection may be greater than is currently recognized." - CDC link, with more info including potential bioterrorism implications
  • emessis


The other day I recalled seeing a drawing of a bilaterally gynandromorphic grosbeak in my ornithology text, and it looks like no one has posted about it, so...

Gynandromorphs are something like hermaphrodites, except that the bodies of gynandromorphic animals are basically split right down the middle, with one side being male and the other female, both internally and in appearance. It seems to be most commonly seen in insects, typically butterflies or moths, but has cropped up in crabs, lobsters, and several bird species.

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Green tea: genmaicha

Bleeding-Heart Doves

I'm a semi-lurker with my first post, checked through and didn't see this one, so here we go. :)

The bleeding-heart doves are several species in the genus Gallicolumba, a genus of ground-doves, that have plumage patterns in red on their chests that look like bleeding wounds--hence the name. Sexes are nondimorphic, so they both have the patterns. They hail from small islands in the Philippines, where most of them are regarded as near threatened to critically endangered due to habitat loss, overhunting, and trapping for the pet trade. One species, the Sulu Bleeding-Heart, has not been reliably sighted since 1891. The exact purpose of the rather realistic marking is undetermined.

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aye aye captain
  • drhoz

Trainspotting and Cunning Little Brain Parasites

In responce to tiny_sparks post

More on the parasite Toxoplasma gondii - the one that breeds inside your brain cells and turns you into a car-crashing schizophrenic. It infects humans, but the primary host is the cat. Animals are infected by eating infected meat, by ingestion of faeces of an infected cat, or by transmission from mother to fetus.

Up to one third of the world's population is thought to carry the infection. Including Martina Navrátilová, for one.

At first, the infection usually causes a mild flu-like illness, or nothing at all. After the first few weeks, the parasite rarely causes any obvious symptoms in otherwise healthy adults. However, people with a weakened immune system, such as those infected with HIV, and fetuses, may become seriously ill, and it can occasionally be fatal. The parasite can cause encephalitis (inflammation of the brain) and neurologic diseases and can affect the heart, liver, and eyes. ( For some reason, Toxo-infection also means you're almost 3 times more likely to have a boy-child, instead of girls )

But the only reason it kills you is because the mechanism it's using to stop you dying, has been been thrown completely off the rails.

Toxoplasma doesn't want you to die. Thus, it uses your own immune system to keep its own numbers in check - deliberately ensuring that any excess Toxoplasma get destroyed by your immune system before they can invade and damage other brain cells.

It does this by subtly tipping the desperate immune response towards white blood cells that eat Toxoplasma as they wander between brain cells. That stops the infection getting any worse, because the ones that are already sitting in little groups of 8 inside your neurons are smugly immune to such attacks, and are willing to wait it out. That way you don't die of out-of-control brain damage before you get eaten by a cat (yes, it isn't supposed to be infecting *you* - it's supposed to cycle between cats and rodents). The symptoms include increased risk-taking - in rats, that means going out to investigate this interesting 'cat' smell, whilst the cat is still around. In humans, you get traffic conditions in Rome.

Unfortunately, if you're a fetus or immune-compromised, you don't have any of those particular white blood cells and the result is massive brain destruction, as the Toxoplasma breed out of control, infecting and destroying every brain cell they come across. That's what happened to the guy in Trainspotting, and one reason AIDS was closely associated with brain damage before the Toxoplasma link was understood.
Call me sir goddamnit!

Velvet (Cow Killer) Ants

When I was a WEE lad living in the hills of Northwest Georgia I would come across these nifty little gals quite often.


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I was trying to find a good reference picture to give an idea of how large these things are but alas...not to be found. Depending on species and size of the developmental host they run anywhere from 1/8" to 1" in length.

And that notion of 'sting painful enough to kill a cow'...yeah I'm still alive after being stung by one but HOOOLLLYYYY FUUUUUUUUUUCK you want to talk about pain? My full-body jelly fish encounter was less painful. :/