People, Parasites, and Plowshares | Dickson D. Despommier

The longest parasite in the world is the fish tapeworm. It can grow to thirty feet, and it is estimated that "twenty million people worldwide harbor this parasite."
The fish tapeworm prospered in the Great Lakes, because, for years, folk knowledge had it that "the best fishing was right through the dump hole of the outhouses located at the end of the [inhabitants'] docks."
More people in the world raise pigs than cows. Why? It's cheaper. Pigs reach adulthood in just six months. Cattle take eighteen months. And, just like humans, pigs will eat anything. "Because of their easygoing lifestyle, in many regions pigs live right alongside people in what is referred to as a peri-domestic relationship." Thus the widespread presence of Taenia solium, the Pork Tapeworm.
A particularly disgusting worm, the "Guinea Worm," infects humans by means of water wells known as "step-wells." Once in your gut, these beasts migrate to your lower limbs, where they form a blister. The most soothing place for a foot with this swelling is the cool water in a well: you stick your feet there, and the offspring pop out at once to infest the water.
The "International Decade for Clean Drinking Water" was instituted to put an end to the Guinea Worm. Do-gooders from WHO and other NGOs suggested that people in infected areas cap their step-wells. But where there is water is a place for "social networking:" e.g., people gather there to gossip. Thus capping was resisted by the common folk.
River blindness --- onchocerciasis --- comes from the black fly. Forty years ago, Merck and Company found a cure, called ivermectin. In 1987, Merck agreed to give away the drug on a global scale "for compassionate use" in Africa, Central and South America. Why? Because river blindness is mostly a disease of the poor, and "no developing country could afford to purchase it." Senator Bill Bradley of New Jersey talked the CEO of Merck into making it available, for free, to the world. To their credit, Merck has now given away over 700 million doses of the drug.
It is estimated that "over 25 percent of what the less developed world eats each day goes to feeding intestinal parasites."
In the past 100 years, more people died of malaria "as now live in the United States." It infects 2,000,000 people annually.
The Cerrado of South America "is home to more species of large mammals than anywhere else on the planet." The Cerrado takes in parts of Brazil, Paraguay, and Bolivia, and almost all mammals there harbor a parasite called Trypanosoma cruzi, Chagas' disease. It is spread by an evil little creature called "the kissing bug."
This is a fascinating book, and I have tried here to point out many of the highlights. But I also should warn you about some of the surprises that pop up, some that may make you wish you had never opened it.
Dr. Despommier is at ease with the bugs, worms, and bichos that afflict so many people all over the world (it has been estimated, for example, that the average Egyptian farmer, in his short life, will end up carrying thirty or more different parasites in his body). But the reader, like me, may have her limits.
For instance, there is a worm known familiarly as Ascaris lumbridoldes. There are an estimated 2,000,000,000 people in the world --- that's a third of the world's population --- infected with this giant (and gross) intestinal worm. The lengthy passage dedicated to the life-cycle of ascaris is rich in detail that, unh, for some of us, might better be left unsaid, especially on page 95, when the resident physician in Babies Hospital finds a young patient with an ascaris crawling out of, cack, his nose.
I had to leave off at that point, hurrying on to page 153 where I found a photograph of a foot heavily infested with Dracuculus medinesis, the worm described above who demands exit in the cool waters of the step-well (thereby infecting the whole well). The photo is a genuine gagger.
I mean, I want to know this stuff, sorta, but I guess one reason I didn't finally end up in medical school was that I figured that sooner or later I would run across the realities of bodily ills that I would rather not know, nor see.
Now all these years later, in this volume, I find them revealed ... mercilessly. Be forwarned.
Despommier has much to teach you. But you may lose something in the process. If you want to break more slowly into the world of vulgar beesties from within without getting weak in the knees, I recommend Lee Goff's charming A Fly for the Prosecution --- How Insect Evidence Helps Solve Crimes (see the penultimate review on the page) ... or, best of all, with a title slightly longer than the nits it introduces, Rats, Lice, and History: Being a Study in Biography, Which, After Twelve Preliminary Chapters Indispensable for the Preparation of the Lay Reader, Deals With the Life History of Typhus Fever by Hans Zinsser. Goff and Zinsser will enlighten you without making you reach for the smelling salts (or retch).