How Can Parasites Benefit Humans?

Parasites are usually considered to be harmful creatures that drain nutrition from their hosts while giving nothing in return. However, speculation exists as to whether or not parasites might actually have a practical function.

Theories/Speculation

• An article published in the British Medical Journal in 1989 suggested that excessive hygiene could be to blame for many health problems like allergies and autoimmune diseases. David P. Strachan, the author, suggested that parasites and bacteria played a role in stimulating the immune system in our ancestors. As of 2010 his theories have not been scientifically investigated.

History

• According to the Health Guidance website, leeches, which are parasites that attach to a host and break the skin to drink its blood, have been used since the 18th century when bloodletting was a popular treatment for disease. ABC News indicates that women ingested tapeworm eggs to help them keep their weight down during the 1950s.

Effects

• Currently, leeches are used to help the skin reattach and promote healing after surgery, and they reduce discoloration in a black eye. The Tapeworm Diet website advocates using worms to control weight and stimulate the immune system, a practice that is banned by the FDA.