A 16-year-old boy is brought to the emergency department for evaluation of testicular pain and scrotal
swelling. He had an episode of bilateral facial swelling along the jawline several days ago with associated fevers, headaches
, and myalgias. The pain is worsened with movement. He has no dysuria. He is not sexually active. Records demonstrate his parents refused vaccinations
throughout childhood. Temperature is 38.2°C (100.7°F), pulse
is 98/min, and blood pressure
is 122/84 mmHg. Physical examination reveals bilaterally enlarged and tender testicles
. Stroking of the inner thigh bilaterally results in elevation of the testes
. Which of the following is the most likely etiology of this patient’s clinical condition?