October 18 - Necator americanus

Necator americanus is a species of nematode commonly known as a hookworm. It has a very broad distribution and has long been common in the Southeastern U.S. The eggs are shed in the host's feces and then they go through several larval stages in the soil. Eventually they develop into filariform larvae, which find a host, often a barefoot kid, and burrow in through the skin in their feet. They will make their way into blood vessels, and eventually find their way to the lungs. They get coughed up, swallowed, and then mature into adults in the GI tract. They use their rather fearsome jaws to latch onto a villus in the small intestine, where they ingest the host's blood. The symptoms can be mild anemia, diarrhea, and cramping but infection can also lead to more serious things such as iron-deficiency and even developmental problems. Sounds pretty awful, right? Yet, believe it or not, many people are now becoming infected with these parasites - on purpose. The reason is that recently it was observed that people in developing countries, where hookworm and other parasites are prevalent, do not very often have auto-immune diseases like allergies, asthma, etc. and it was hypothesized that our hyper-sterile Western lifestyle that has led to "bored" immune systems that turn on our own bodies. Helminthic therapy is a new movement whereby people purposefully expose themselves to worms such as hookworm in an effort to keep their immune system busy attacking the parasite so that it doesn't cause these other problems. A documentary about this new therapy has been made - you can learn more about it here.