The immunoperoxidase method for rapid diagnosis of Herpes simplex encephalitis (HSE) using touch preparations.

Ten rats were inoculated intracerebrally with Herpes simplex virus type I to study the possibility of establishing a rapid diagnosis of Herpes simplex encephalitis through examination of touch preparations of brain tissue stained by the immunoperoxidase method. All except one of the animals died within four days of the developing encephalitis. The surviving animal was killed on the fourth day. Touch preparations were shortly fixed in 4% buffered formalin, cold acetone, or alcohol. The indirect immunoperoxidase method was used to identify viral antigen. The authors found that formalin serves as a good fixative and sensitivity as well as specificity is high. The diagnosis could be made within 4 hours. The cellular morphology is retained. The reaction product is stable and background staining no problem. The results of this study imply to use this method also for rapid diagnosis of brain biopsy tissue in human infections.