Q. A 45-year-old male presents to the emergency department with a two-week history of fever, malaise, and headache. The patient’s wife reports he has experienced headaches, nausea, vomiting, photophobia, and progressive weakness in his extremities that worsened over the course of a week. Earlier today, the patient reportedly had “spasms” when he attempted to drink fluids. His wife is also concerned because the patient appears anxious and “not himself.” The patient’s past medical history is significant only for hypertension. Additionally, his wife reports the patient was exposed to a bat in their garage six weeks ago. She states the patient may have been bitten, and refused to pursue medical treatment, stating it was “just a scratch.” On physical examination, the patient is alert but disoriented. His temperature is 38.5 degrees Celsius (101.3 degrees Fahrenheit), blood pressure is 130/85 mm Hg, heart rate 100/min, respiratory rate 35/min, and oxygen saturation is 98 percent on room air. The patient's Glasgow Coma Scale score is 12. You note hyperactive deep tendon reflexes, a positive Babinski sign, and evidence of neck and limb stiffness. You order a CT scan of the patient's brain (see image), which shows increased signal in the posterior part of the medulla oblongata and in the basal ganglia, and evidence of cerebral edema and hydrocephalus. Assuming the most likely etiology of this patient’s symptoms is viral zoonotic transmission, which of the following therapeutic interventions is most indicated at this time?