> Unexpectedly, guanabenz caused nearly half of the chronically infected mice to die within the first 10 days of drug treatment (Fig. 6B). Mice that succumbed to the guanabenz treatment developed classic symptoms of Toxoplasma encephalitis, including lethargy, tremors, paralysis, and seizure. None of these mice showed signs of active infection at the start of guanabenz treatment. These results suggest that the mice experienced reactivation of encysted parasites rather than continuation of a severe acute infection, but we cannot rule out the presence of lingering tachyzoites at the start of drug treatment. The mice that survived the full drug treatment did not display any symptoms of Toxoplasma encephalitis.
So in this case reactivation allowed the immune system to fight and destroy the infection (for those that survived).
I don't really understand the part in the abstract about there being a reduction in symptoms despite no reduction in cyst burden (that this was not necessary for a response). Could someone explain?