Which nematode infection is acquired from undercooked pork and causes myalgia with cysts in muscle?

• A. Taenia solium
• B. Trichuris trichiura
• C. Ascaris lumbricoides
• D. Trichinella spiralis

Answer: (D)

The infection being tested is caused by a nematode acquired from eating undercooked pork, and it classically presents with muscle pain because the larvae migrate to and encyst in striated muscle. After ingestion, the larvae are released in the intestine, mature, and then disseminate to muscle tissue where they form cysts (nurse cells). This leads to myalgias, fever, edema, and sometimes periorbital swelling, with eosinophilia on labs. Prevention is cooking pork to safe temperatures, and treatment involves antiparasitic drugs, with steroids if the inflammation is severe.

The other parasites don’t fit the exact scenario: a pork tapeworm is a cestode and can form tissue cysts, but it’s not a nematode and its clinical picture centers more on intestinal symptoms or neurocysticercosis rather than muscle cysts with myalgia. Whipworm and Ascaris cause gastrointestinal and systemic symptoms but not the characteristic muscle-encysted larvae after undercooked pork.