Ascariasis

Ascariasis is a parasitic inflammation caused by a type of roundworm. It is very common in tropical climates with poor hygiene and is thought to infect over 1.5 billion people worldwide. The parasite rarely causes any symptoms, and in most cases these are limited to mild inflammation, fever and diarrhea. However, if the parasite infects other organs, it can cause serious symptoms and death.
Like many parasitic roundworms, the eggs are excreted in the host's feces. When feces tainted food is eaten by a new host, the eggs hatch and grow in the intestines. The disease is not contagious and cannot be passed from human to human. 
Diagnosis is usually from finding the worms in the host's feces or vomit. 
Over half a dozen anti-parasitic medications are effective against the worm, but prevention efforts are more important, such as using proper toilet facilities and avoiding tainted food. 
Ascariasis at NIH
Ascariasis at Wikipedia
Ascariasis at Mayo Clinic