USMLE practice question 1: ID level: easy

Question

A 45-year-old female immigrant from Russia presents with Vague abdominal pain and fatigue. CBC shows hemoglobin of 9.5 with MCV of 102. Eosinophils 1.8X 10 9th.

How did the patient acquire this infection?

A. Eating undercooked fish

B. Cleaning her cats litter box

C. Mosquito bite

D. Walking barefoot on the soil

E. Drinking contaminated water

Answer 1

A. Eating undercooked fish

This is the most important fish borne zoonoses with over 20 million people affected worldwide. It is present in many areas of developed world and prevalence in areas are changing. For the test I would bet most likely they would use Russia or Scandinavian/Baltic states. This cestode/tapeworm/ribbon-like worm absorbs 80% of dietary B12 so a Macrocytic anemia is often present. As any parasite can there is often an elevated eosinophil count. They can also calls abdominal pain, intestinal obstruction, or be basically asymptomatic.