Answer: Strongyloides stercoralis - adult female and larvae
This was an unusual case because adult worms were present in the stool specimen, likely correlating with the heavy infection in this patient. Dr. Ribes, who kindly donated this case, resides in one of the rare areas of the United States where strongyloidiasis is still endemic (Kentucky) so she gets to see a fair amount of this infection. She shared with me that she has only seen adults in the stool once or twice in fthe past.
Here is a shot that shows both a larva (probably rhabditiform) and adult female: