Prophylactic Therapy of Japanese Encephalitis Passive Immunization Combined with CO2 Inhalation.

Abstract

Combined treatment with AB followed by exposure to CO₂ protected a significant proportion of mice against lethal infection with JEV when treatment was started on the 4th day after inoculation, before disease was evident. (Variance ratio by analysis of variance for AB-CO₂ treated mice vs untreated controls greater than 0.01%.) AB alone was much less effective. We have not shown that the passage of AB into CNS tissue was increased by CO₂ treatment but this is the most reasonable explanation of our results in view of the adverse effect of CO₂, and the limited protection by AB alone. When the first treatment was delayed until the fifth or sixth day, there was no protection and most patients with JE are not seen by physicians until one or more days after onset of encephalitis. Thus effective therapy of human JE by this method is not promising.