Nanosilver hydrosol is my recommendation for this condition. The nanoparticles are most effective in a range of one to ten nanometers, which allows them to penetrate the blood-brain barrier. Silver nanoparticles are widely used to kill amoeba in high-end hot tubs instead of chlorine, and have been in-use in treating human diseases since before penicillin, and are still the treatment of choice in the protection of burn victims from infection. There is virtually no toxic limit with silver, but nanosilver hydrosols are effective in minute doses (@ 10-20ppm, 15ml/day), so toxicity shouldn't be considered a problem.
The nanosilver hydrosol should be administered by IV for best effect.