Strongyloides stercoralis

A 48-year-old man presents to his primary care provider for evaluation of dull abdominal pain that has been ongoing for the past three months. The pain is intermittent, and poorly localized, but has been increasing in severity. He has also experienced frequent episodes of coughing that sometimes produce bright red blood. Past medical history is notable for hypertension and hypercholesterolemia. The patient works as a farmer and often walks barefoot through the fields. Temperature is 37.0°C (98.6°F), blood pressure is 152/90 mmHg, and pulse is 82/min. The heart and lungs are clear to auscultation. Mild pain is elicited with palpation of the abdomen. Scattered serpiginous rashes are present in the lower extremities. Initial blood work reveals eosinophilia. One of the three stool samples shows larvae. Which of the following pathogens is most likely responsible for this patient’s symptoms?