Answer to Case 708

 Answer to the Parasite Case of the Week 708: Trichinella sp. larva; coiled within a muscle "nurse cell". Larvae are the only form seen in muscle with this infection. Compare this to our recent case of Haycocknema perplexum infection in which gravid female worms were seen 'crawling' through the muscle fibers. These two helminths are also quite different than muscle infection with the protozoan parasite, Sarcocystis, as shown in Case 707. Keep an eye our for our next case that will show a very different parasite in muscle! 

Trichinella sp. larva within muscle: 

Note the presence of stichocytes - tall cells that make up an organ called the schichosome.

Dr. Richard Bradbury was kind enough to donate the following case showing BOTH Trichinella and Sarcocystis in muscle. This is quite the impressive infection!