Enterobius vermicularis

History of Discovery

The first evidence of pinworm infection dates back to Roman-occupied Egypt (30 BC-AD 395), and the oldest known pinworm ova have been found in human coprolites dating back to 7800 BC from Danger Cave, Utah (Fry and Hall, 1969). Pinworm has also been found to be referenced in the ancient writings of Hippocrates, dating back to 430 BC.

Ferreira et. al in 1997 and Hugot et. al in 1999 established pinworms as an example of an inherited parasite, meaning it is a host-specific parasite that has a long history of co-evolution with ancient human ancestors dating back to Africa before human dispersion across the continents.

Ancient pinworm finds have occurred in a variety of archaeological sites, and according to Goncalves et. al in 2002, the majority have been from coprolites from sites in the USA , with two from Chile and one each from Peru, Mexico, Germany, Denmark, and Argentina, as well as one finding from a Han dynasty mummy in China.

Picture from: http://www.gc.maricopa.edu/earthsci/imagearchive/fossils.htm


Pinworm findings in archaeological material outside the New World have been scarce for unknown reasons, and it is hypothesized that this parasite did not originate in the Americas, but rather arrived via land route through the Beringia. Pinworm is one of the few helminths that could have possibly arrived through this route, as most helminths require a particular soil temperature to progress to the infective stage, a stage pinworms do not require and would not have been possible to attain through migration in the cold northern territories.

Picture from: http://www.rootsweb.com/~akahgp/Social/beringia.htm






A supposed second species of pinworm has been documented in Europe, Africa, and Asia. Known as Enterobius gregorii, this parasite was isolated in 1983 by Jean-Pierre Hugot. The morphology, life cycle, clinical presentation, and treatment for this parasite are identical to Enterobius vermicularis, and the only difference lies in the fact that E. gregorii possesses a smaller spicule (70-80 micrometers versus 100-122).