|Description:||A composite of three different photomicrographs, this image compares the size relationship between three different parasitic eggs. From left to right: the egg of a Diphyllobothrium latum tapeworm, the egg of a Paragonimus westermani lung fluke, and the egg of the giant intestinal fluke, Fasciolopsis buski.|
A parasite is an organism that lives on or in a host and gets its food from or at the expense of its host. Parasites can cause disease in humans. Some parasitic diseases are easily treated and some are not. The burden of these diseases often rests on communities in the tropics and subtropics, but parasitic infections also affect people in developed countries.