Review Question - QID 210483

A 10-year-old boy is brought in to the emergency room by his parents after he complained of being very weak during a soccer match the same day. The parents noticed that yesterday, the patient seemed somewhat clumsy during soccer practice and was tripping over himself. Today, the patient fell early in his game and complained that he could not get back up. The patient is up-to-date on his vaccinations and has no previous history of illness. The parents do report that the patient had abdominal pain and bloody diarrhea the previous week, but the illness resolved without antibiotics or medical attention. The patient’s temperature is 100.9°F (38.3°C), blood pressure is 110/68 mmHg, pulse is 84/min, and respirations are 14/min. On exam, the patient complains of tingling sensations that seem reduced in his feet. He has no changes in vibration or proprioception. Achilles and patellar reflexes are 1+ bilaterally. On strength testing, foot dorsiflexion and plantar flexion are 3/5 and knee extension and knee flexion are 4-/5. Hip flexion, hip extension, and upper extremity strength are intact. Based on this clinical history and physical exam, what pathogenic agent could have been responsible for the patient’s illness?