What species of Strongyloides is this?

Most infections with Strongyloides are due to the species, Strongyloides stercoralis. This is a persistent and dangerous parasite that can cause serious disease and occasionally result in death. Most laboratories assume that any Strongyloides is S. stercoralis. This is justified since this is the most prevalent and cosmopolitan species.

However, humans can be infected also by:

  • S. fuelleborni, a parasite of non-human primates from Africa; and
  • S. kellyi, found only in humans in Papua New Guinea.

By examining faeces where the Strongyloides has gone through the indirect life cycle and developed to free-living females and males, it is possible to identify the species.

This Powerpoint file was developed to illustrate how this is done using the morphology of free-living females.

View PPT file Are these worms Strongyloides?" (2.6 Meg)

Created by Rick Speare 10 May 2013