Schistosomiasis – it's a big name for a microscopic little worm. Mostly they live in water snails, and around here, they don't cause much more than a rash explains Case Western Reserve University's Charles King, an expert on global health and diseases.
KING: The closest thing we have in North America is what's called "Swimmer's Itch". Everybody in the upper peninsula of Michigan and Minnesota and Wisconsin knows that certain lakes you go in, in the summer, where snails abound, you're liable to get this skin rash which is caused by these little larvae that attempt to get through the skin.
But in some places, they've adapted to living in humans. They crawl through the skin – and make people sick -- infecting the lungs, heart, liver and eventually make a healthy living feasting off the digested food that passes across the human intestinal wall. And then they mate – and their eggs pass, in the normal way, back outside the body, where they can infect someone else.
Just the idea of these creepy crawlies is enough give most westerners who have access to clean, uninfected water the heebie jeebies. But for many people living in third-world countries, kitchen, laundry and bathroom facilities are all supplied by the local lake or river. And these worms are making them sick. But the question facing public health researchers is: what to do?
KING: What the Chinese did was actually turn the latrines into bioreactors, so that the human manure actually gets composted, and as a byproduct they generate methane which can be used as kitchen fuel.
He says that converting human waste into fuel, actually saves money for the household, is environmentally friendly, and kills the parasites eggs at the same time. That, combined with better access to clean water sources for cooking, drinking and bathing, and replacing livestock with machinery for water farming, made a bigger impact than just treating individual infections with expensive drugs.
Because the infections are sporadic, not usually deadly, and impact some of the world's poorest people, King says it's a disease that's gone largely unnoticed. In fact he calls it the most common disease nobody's ever heard of - despite the fact that it infects as many people as Malaria. And it's not just locals – but tourists too who should take care.
KING: It can take 30 seconds or less of exposure for somebody to pick up an infection. That's a challenge for our travelers now too, when they go on eco-tours or white-water rafting they may actually be going through habitat that's very good for transmitting Schistosomiasis.
King says, the disease can be treated with drugs, and travelers in areas prone to schistomaisis or other parasites can have a blood test when they return to check for exposure.
Gretchen Cuda, 90.3