Base on an article I read, the flagellates may be found in the following parts of the human body:
1) reproductive tract,
2) alimentary canal,
3) tissue sites and also the blood stream,
4) lymph vessels and cerebrospinal canal
But, majority of the flagellates are found in the alimentary canal also known as digestive tract. It is composed of the mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anus, in that order.
