Early diagnosis of virus-caused vesicular rashes by immunofluorescence on skin biopsies. II. Poxvirus (vaccinia).

Immunofluorescence (IF) was used to demonstrate vaccinia virus antigen in frozen sections of skin biopsies from the site of revaccination in 42 individuals. The immunoglobulin (Ig) of a rabbit anti-vaccinia serum and the Ig of the pre-immune serum conjugated with fluorescein-isothiocyanate (FITC) was employed. 11/13 biopsies taken 1 day after vaccination were positive in the IF test as were 13/13 biopsies taken 2 days and 14/16 biopsies taken 3 days after vaccination. Even minute quantities of virus antigen were easily detected. The applicability of the test and the advantage of using biopsy material in early rashes of vaccinia and variola is discussed. The reliability of the direct IF using conjugated antisera against vaccinia-variola, varicella-zoster and herpes simplex virus for differentiating between maculopapular rashes was proved in a coded test.