Remember the old X-Files episode about the half-man-half-Flukeworm living in the sewers? The real thing is even scarier.
At least there's no chance of accidentally ingesting the Flukeman, or carrying him around in your innards for years while he fills you up with eggs. Some sources say the average American male is packing around up to 2 lbs of intestinal parasites inside of his body. And not only are the great outdoors teeming with intestinal flukes, there are also liver flukes, lung flukes, and - scariest of all - blood flukes.
Blood flukes, known as Schistosoma or Bilharzia (so named for its discoverer, German pathologist Theodor Maximilian Bilharz), are the World Health Organization's second biggest concern after Malaria. They cause a condition called Schistosomiasis that affects hundreds of millions of people around the world.
Then there's the thread-like filarial nematodes, which can be transmitted by mosquito bites. I found this factoid about them most fascinating, from Wikipedia:
Filariasis is usually diagnosed by identifying microfilariae on a Giemsa stained thick blood film. Blood must be drawn at night, since the microfilaria circulate at night(nocturnal periodicity), when their mosquito vector is most likely to bite.
Paragonimus kellicotti was first identified in Kentucky, and though it was originally believed to be primarily a North American parasite of snails and crustaceans, it has since spread worldwide and has been found in cats, dogs, minks, muskrats, and, yes, humans. I've always maintained that anything can jump species if it really wants to, and if given the opportunity.
And then there's the scientists who, being scientists, decided to round up 176 frogs and toads from Kentucky and Indiana and cut their lungs open just to see what they'd find. The results were: 412 H. complexus, 63 H. longiplexus, 23 H. breviplexus and 8 H. varioplexus. That's a grand total of 506 lung flukes for 176 frogs. Yum!
And then according to this study, "a survey of 36 cats within a 250-mile radius of Fort Knox, Kentucky, revealed that 5 of these cats had pancreatic flukes". (Uh... will someone explain to me why they chose Fort Knox as their epicenter?? Please?)
Should I mention the Flukes found inside Catfish in Kentucky Lake? Or that the Beef Tapeworm can grow up to 40 feet long inside your intestines? Nah. I'm making myself queasy here.