Rapid Diagnosis of Varicella-Zoster Infections by Agar-Gel Diffusion

Vesicular fluid and crusts from patients with clinical varicella, zoster, and other vesicular skin eruptions were tested by the gel-precipitin technique for demonstra-tion of specific antigen. With use of reactive varicella-zoster (V-Z) antigen as a control and corresponding antisera, the gel test proved to be a simple, specific, and sensitive procedure for the rapid diagnosis of V-Z infections. The need to identify vesicular rashes in patients suspected of having smallpox has led to the de-velopment of a variety of laboratory tests. Be-cause of its simplicity, the gel-precipitin test has been widely used to make a presumptive diagnosis of smallpox in such patients. A negative test for smallpox antigen, however, still left the diagnosis in doubt. Therefore, there was a need for methods to identify antigens of other agents that might cause similar diseases. By adaptation of the gel-precipitin technique for varicella-zoster (V-Z) virus [1], it has been possible to identify antigens in vesicles of patients with varicella [2, 3]. The purpose of this investi-gation was to determine the clinical usefulness of this technique and its sensitivity and practicability compared with viral isolation. Materials and Methods Test material. Specimens of vesicle fluid and crusts were obtained from patients with chicken-pox, zoster, and other vesicular eruptions. When-ever possible, multiple specimens were obtained from the same patient at various intervals after the onset of rash. Vesicles containing clear fluid Received for publication February 29, 1972, and in revised form June 5, 1972. This study was supported by grant no. S2I181/1