Re: Dinosaur parasites

[Michael Corriss <mcorriss@gate.net>]

Hello.

A few comments bundled below.
Unfortunately I can't remember Dan's "suicide snail" culprits, my
 old head is slow, my old notebook is nowhere to be seen and my
 old computer dead from malevolent spyware.

>Robert J. Schenck:
>There is, for example, a species of parasite that
>infects ants, and "takes over" their behaviour. 
>It makes them crawl to the top of grass blades
>and cling on with their pinchers, to make them
>more likely to get eaten by grazzing cattle (the
>next step in the parasite life cycle).  In fact,
>this organism is so specific that it will
>'relinquish' control during noon-time, when the
>sun is very high, so that the ant can return to
>normal behaviour to avoid dying from the heat.

That's _Dicrocoelium dendriticum_, a trematode that infects 
sheep, goats, cattle, cervids, and pigs and has abandoned an 
aquatic stage in its life cycle. The miracidium containing egg 
has to be eaten by a snail ( _Cionella lubrica_, here in the US ) 
to hatch into Mother sporocysts which then produce daughter sporocysts . 
Finally developed xiphidiocercariae migrate to the mantle cavity 
"lung" which I guess is pretty irritating since the snail exudes excess 
mucus and leaves little cercariae filled slime balls along the way. 
The cercariae still have well developed tails reminiscent of recent 
ancestral dispersion in water, must be difficult swimming in that mucus.

_Formica fusca_ is the US slime feeding ant that who hosts 
development of the metacercariae. All it takes is one of perhaps 
a hundred metacercariae to encyst proximal to the sub-esophageal 
ganglion and the ant will do his climb and clamp-on whenever the 
temperatures drops.
Another dicrocoeliid _Brachylecithum mosquensis_ similarly 
infects carpenter ants ( _Camanotus sp._ ) which causes it to 
wander around in the light a perfect target for a hungry robin. 
I don't remember if that's temperature dependent. It excysts 
in the duodenum and the fluke travels up the bile gradient to 
mature in the liver. Estimated 50,000 _D. dendriticum_ up to 
a centimeter long in a badly infected sheep liver.
Always been one of my favourites after the Apicomplexans.
 
>Dora Smith:
>Today's dinosaurs get giardia, coccidians, 
>trichowhatsits, roundworms, tapeworms, pinworms, 
>and in short just about everything mammals get. 
>Often they get the same species or different 
>species of the same genus.They 
>also get itchy overgrowths of candida.

Little parasites can cause big morbidity. A case of _Giardia 
lamblia_ in an immunocomprimised patient's biopsy showed 
not a single gap between the organisms suctioned to the 
intestinal wall, blocking all absorption. The numbers in the 
stained stool slide was staggering.

About 25 years ago, a friend made a dubious purchase of 
3 parrots. They seemed to be alternating between drooping 
as if asleep and agitated. A drop of blood from a wingtip 
revealed 10% erythroparasitemia of malaria ( _Plasmodium sp._ ) 
in the worst one, all infected. Customs said that all the seller's 
birds were infected. He was in jail, last I heard of it. 

_P. Falciparum_: My father said his urine turned dark red 
and he thought he'd shake his bones through his skin, he was 
so cold, even though he had four blankets on top of him in the 
110 degree Guadelcanal jungle. But he was happy, at least he 
got to sleep on a dry army cot, which would walk around the 
tent when he shook. 
Malaria's the biggest morbid and mortal malady for humans, 
no doubt it takes a large toll on birds, too.


>Phil Bigelow:
>A palynologist friend once told me that there 
>can be many tens of fossil worm egg cases, 
>protozoa cysts and bacteria spores in a 
>one gram sample of Hell Creek Fm. mudstone 
>(that's a *randomly collected* sample).  Few
>palynologists are studying these microfossils, 
>because their taxonomic affinities are hard 
>to pin down. (these non-pollen fossils are put in
>either the "other" category or "unknown" category).

Which only increases my chagrin at the failure of Dania, 
Florida's Graves Natural History Museum. I don't know 
when or where the Lancian _Edmontosaurus_ we worked 
on will be finished or mounted but more than that - the two 
large barrels of matrix that came from the more than 300 
field jackets won't pass beneath my microscopes' objectives. 
I wanted to look for any formed elements, grain by grain, 
before I tried to learn how to disolve stuff with the HFl to 
grab the pollen. 

-mpc 
Michael Patrick Corriss
Miami Beach, FL