Strongyloides eggs can be easily distinguished from the eggs of trichostrongyles that infect ruminants because Strongyloides eggs are slightly smaller and contain a larva when passed in the feces. Trichostrongyle eggs will not be larvated in a fresh fecal sample, but they may larvate in the sample if stored incorrectly. This video of Strongyloides shows motile larvae to the left of a typical trichostrongyle egg. A large air bubble is also present to the left of the Strongyloides egg.
Courtesy of Dr. Grace VanHoy.