Review Question - QID 214464

A 3-year-old boy is brought to the emergency department by his mother after he is found unresponsive in his crib. The mother reports that the patient has had several days of sore throat, loss of appetite, and fever, which had been getting better. This morning, the patient had an episode of vomiting despite not eating much and has been lethargic for several hours. Earlier, the patient had been complaining of a headache, before being found unresponsive but breathing in his room. On exam, the patient's temperature is 98.8°F (37.1°C), blood pressure is 108/76 mmHg, pulse is 90/min, and respirations are 14/min. The patient withdraws to pain but otherwise does not respond. There is a faint rash on his palms. There is no neck stiffness, and Kernig and Brudzinski signs are negative. The mother reports that she had attempted treating the patient at home. Which of the following is the mechanism of the likely agent?