Sensitivity of the virus isolation and immunofluorescent staining methods in diagnosis of infections with herpes simplex virus.

Tissues from marmoset monkeys infected with herpes simplex virus (HSV, Herpes-virus hominis) were utilized to evaluate the relative sensitivity and limitation of the virus isolation technique and the immunofluorescent (fluorescent antibody or FA) staining method for diagnosis of HSV infection. HSV encephalitis and/or disseminated infection in marmosets were established by intracerebral, intramuscular, or intravenous inoculation of the virus. Brain tissues, liver, spleen, kidney, adrenal gland, lymph node, and lung were harvested and prepared for the virus isolation procedure in tissue culture and for direct FA staining. Data from six marmosets infected with HSV type 1 and two infected with type 2 indicated that the virus isolation method was more sensitive and reliable than the FA staining technique. False-negative results by FA staining were found in two situations: (1) presence of focal lesions that were missed by the frozen sections, and (2) presence of low concentrations of virus in tissue (is less than or equal to 3.5 log10 50% tissue culture infective doses/g). FA staining provides a rapid method for detection of viral antigens, but isolation of virus in tissue culture is required for a conclusive diagnosis of active infection.