Note: If you have not read the initial case, please go back and check out: Diagnostic Dilemma #2

See below for the solution:

The organism seen moving away from the center of the plate is Strongyloides stercoralis, an intestinal nematode that causes infection in humans usually via direct penetration of human skin when it comes in contact with soil, where the larvae of this parasite resides. Once inside the body, the larvae migrate to the small intestine, mature and lay their eggs within the intestinal lumen. Once the eggs hatch, the new larvae are either excreted into the stool, or penetrate through the intestinal lumen and into the blood, in order to re-start the cycle of infection from bloodstream back into the gut (this is known as auto-infection). This process can remain sub-clinical for years, until the human host develops an immunosuppressive state (through medications, malignancy, HIV, etc.), at which point an accelerated form of auto-infection (known as hyper-infection) can occur. In this scenario, bacteria from the intestinal lumen can translocate into the blood along with the parasite, resulting in enteric sepsis, meningitis and endovascular infection. Patients with Strongyloides often have peripheral eosinophila, and individuals who present with this finding should be screened for this parasite if they come from an area endemic to Strongyloides, especially if there are plans to start immunosuppressive medications. Diagnosis is through detection of larvae in the stool or antibody testing; treatment is achieved with a single dose of Ivermectin therapy (sometimes repeated x1 at 2 weeks).  

Hope you enjoyed this case! Please feel free to leave comments/suggestions!