The Alien Lives of Parasites
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        -A female blood fluke spends its life of constant intercourse lodged in a groove along the 
front of the larger, canoe-shaped male. These tiny flatworms cause little harm themselves, but 
their thousands of spiny eggs trigger immune system reactions that can lead to tissue 
damage and internal bleeding. They inhabit the blood vessels serving the intestines.
        
        -Female "chigoe" or "sticktight" fleas (also known as "jiggers") dig themselves into the flesh 
of their hosts, which can include man. Once fertilized by a free-roaming male, the female's 
midsection expands "like a life preserver," making it more difficult to remove as it eventually 
swells to the size of a pea. After she deposits her eggs, the bloated insect dies, still buried 
under the host's flesh and often causing secondary infection.
        
        -Wuchereria bancrofti is a microscopic nematode responsible for one of the world's 
strangest and most debilitating diseases: elephantiasis, characterized by extreme, incurable 
disfiguration and massive growth of the legs and genitalia. These worms inhabit the lymph 
nodes and ducts, resulting in blockage and swelling of tissues.
        
        -The life cycle of the lancet fluke (Dicrocoelium dendriticum) goes as follows: adults inhabit 
sheep or other grazers, releasing eggs that are spread in manure. When swallowed by 
scavenging snails, the eggs hatch and the parasites are eventually coughed up by the snail in 
balls of slime, which are then consumed by ants. Late in the evening as the temperature 
drops,  infected ants experience an uncontrollable urge to wander from their colony, climb a 
blade of grass and attach to the tip by their jaws. The ants will remain in this position until 
accidentally eaten by a large, grazing mammal... beginning the cycle anew.
        
        -Cattle avoid eating near their own manure, which may contain thousands of expelled 
parasites, but one parasitic fungus increases the odds of reinfection by "firing" its spores up 
to several meters away... and another parasite, the lung worm Dictyocaulus arnfieldi, climbs 
atop these spores to hitch a ride.
        
        -The infamous Oestridae, or "bots," are a family of flies whose large, spiny larvae live 
parasitically in the bodies of mammals. Some species inhabit the nostrils or digestive tracts 
of their hosts, while others burrow into the skin and excavate a large mucus-lined chamber. 
Only one species is known to attack humans, but actually lays its eggs on the bodies of 
mosquitoes. This allows the tiny maggots to be delivered by a much smaller, stealthier insect 
than their mother. Once buried into human flesh, the baby bots can grow up to three inches in 
length and cause considerable pain.
        
                                        -A recently identified nematode parasite alters the coloration of its ant host's abdomen to 
resemble a local berry. When mistakenly eaten by a bird, the parasite completes its life cycle 
and spreads its eggs in the bird's droppings, much like the Leucochloridium.
        
        -The "Gordian" or "horsehair" worm Spinochordodes tellinii is a parasite of grasshoppers in 
its larval state, while aquatic and free-living as an adult. At maturity, it induces its insect host to 
seek out a body of water and drown itself.
        
                                -For nearly every warm-blooded species known to man, there is at least one species of louse 
uniquely adapted to its body; above are the lice of a pigeon, elephant and gopher. 
Monotremes (platypi or echidnas), Cetaceans (whales or porpoises), pangolins and bats are 
the only mammals without lice of their own, and we humans are the only species to host more 
than one variety, both of which we contracted from other primates; human head lice are also 
the lice that infest chimpanzees, while our body lice originated from gorillas. It was by hunting 
and feeding on these apes that our ancestors would have picked up these insects, which 
adapted to the two different types of hair that grow on our bodies (another unusual trait among 
mammals.)
        
        
                -Among the few vertebrate parasites known to man, the degenerate "pearl fish" dwell within 
the anal cavities of sea cucumbers (Echinoderms related to starfish) and nibble on the 
surrounding tissues. Fortunately, their home can regenerate quickly. Their thin, tapered tails 
are perfectly adapted to help force their bodies in and out of their home. Ouch.
        
        -Potentially the most obscure animal on this entire page, the aquatic larva of the Spongilla fly 
feeds exclusively on the tissues of freshwater sponges, which I'm not surprised you never 
knew existed.
        
                
        
        
          
            
              Written by Jonathan C. Wojcik - Photo credits unknown or from public news outlets.
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                                                                Degenerate. Lowly. Primitive. These are terms which, to many people, are immediately 
brought to mind by the word "parasite." Even science was once guilty of labeling 
parasitic life as a sort of "de-volution," a slothful step back for creatures that couldn't cut it 
on their own. Little did we realize, survival in the body of another creature entails extreme 
adaptation which, more often than not, surpasses the sophistication and craftiness of any 
"free living" life-form.
        
        As you read this, every macroscopic animal 
on this planet is harboring at least one 
species of parasite in or on its body, 
including yourself. With more discovered year 
after year, parasitic species may easily 
outnumber the non-parasitic, and their 
tremendous importance to the ecosystem 
becomes more apparent the more they are 
observed.
Parasites have an influence on which animals 
are preyed upon, which animals mate and 
which animals evolve. There is even strong 
evidence that some or all human behavior - 
our tastes in the opposite sex, our sleeping 
habits, our every mental quirk - is subtly 
manipulated by the microorganisms that 
invade our bodies.