January 13th, 2008

aye aye captain

Fear My Deadly Elbows

Slow Loris - Small nocturnal prosimian primates with poisonous elbows. Found from Bangladesh to the Philippines .

Hey, how about that! No parasites today. Lorises lick their elbow glands to give themselves a venomous bite, and as a general defence in case something tries to bite them. I mention them only because Slow Lorises possess what might be the least threatening threat display of any animal in the world

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aye aye captain

If You Want Me, I Shall Be In The Spleen

Parasitic filarial nematodes, and their larval stages, are responsible for heartworm, filarial elephantiasis,river blindness, loa loa, and Strongyloidiasis. Strongyloides is an unusual one - it infects baboons, chimps & humans, & it's equally happy as a parasite and as a free living nematode.

Most of you should know elephantiasis - it's caused by Wuchereria bancrofti, Brugia malayi, and Brugia timori, all transmitted by mosquitoes. The parasites occupies lymph vessels that drain the lower extremities, producing massive enlargement and deformity of the legs and genitalia. However, it is unclear whether the swelling results from the obstruction or from the immune response to the parasite and their endosymbiotic bacteria, Wolbachia, which I'll discuss later as horriible gender-bending parasites of many insects, but seems to be a both symbiote of filarial worms and the cause of their virulence.

Lymphatic filariasis currently affects around 120 million people in 80 countries. The Japanese artist Hokusai, who painted the "36 Views of Mt Fuji", also painted a Japanese sufferer who was wheeling his balls around in a wheelbarrow. (If you're ever in Tokyo, visit the Meguro Parasitology Museum. I could have gone to Disneyland or the Parasite Museum that day. Guess what I chose.)

Guinea Worm is another I'll cover later - it's the largest tissue parasite humans suffer.

River blindness, on the other hand, occurs when the microfilaria of Onchocerca volvulus migrate up into the skin or cornea waiting for blackflies. Your immune system response horribly blotches or scars your skin, eventually causing 'leopard skin' and blindness.

Loa Loa is a good one too - deer flies are the vector. The adults migrate all thru your body - scarring tendons, crippling joints, and best of all

CRAWLING THRU YOUR EYES


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The microfilaria, on the other hands migrate all thru your organs, spending most of the day in your lungs but gathering under your skin at dusk so the mosquitoes can drink them up. We don't know how they know, but it certainly makes diagnosis difficult if you take a blood sample at the wrong time of day. We know that heartworm in dogs (and as recently discovered, even worse in cats) does the same thing, and it's likely elephantiasis has a similar diurnal cycle.

There's a reason that these and so many other parasitic diseases of humanity, including Schistosomiasis, malaria,various tapeworms,african sleeping sickness, Marburg Virus, Ebola, Lassa Fever & too many other viruses to mention, originate in Africa - it's where we and our relatives evolved, and our parasites evolved with us.

Aren't we lucky that our parasites love us so...
aye aye captain

Kaboom!

In response to the Exploding Ant post - yes, I'm gradually working my way back, hopefully I won't have too many other reposts -

Globitermes sulphureus, the exploding termite.

Given the sheer number of termites (in Australian ecosystems they take the place of Wildebeest herds, and other large herbivores) and species thereof, it's not surprising that they've invented many different ways to protect their nests from all the things that want to eat them. And from each other.



Many species have soldier castes with enormous jaws, and most bang their heads vigorously against the wall to summon reinforcements (curious to listen to, when you're working under a house investigating the extent of an infestation, and when you tap at the wall it taps back).

Other simply plug the hole in the defences with their own heads, until the workers can seal it off.

Some species go further. Nasutitermes sprays glue from a nozzle on their foreheads.

And Globitermes grabs an enemy in it's big curvy jaws, and explodes. aka "Suicidal defensive behaviour by frontal gland dehiscence in Globitermes sulphureus. The result is a dead termite and an invader glued to the spot.