Application of the immunofluorescent technic to the study of pathogenesis and rapid diagnosis of viral infections.

Abstract

A few examples of the use of the immunofluorescent (FA) technic for study of pathogenesis and rapid diagnosis of viral infections are cited. When ferrets were experimentally infected with influenza virus, direct FA staining has demonstrated that the ciliated columnar respiratory epithelial cells lining the nasal turbinates were the primary sites of virus multiplication. Examination of desquamated epithelial cells in nasal smears from influenza-infected ferrets as well as from human patients during several epidemics enabled various investigators to make a rapid diagnosis of influenza infection. In measles infection, FA staining of urinary sediment smears showed the presence of fluorescent cells containing specific measles antigen. These fluorescent cells were detectable during a period of 2 days before to 5 days after the appearance of the morbilliform rash, allowing a rapid diagnosis of measles in 36 of 38 confirmed cases. Among seven cases of human encephalitis caused by Herpesvirus hominis , examination of brain specimens (three from biopsy and four from autopsy) by FA staining showed the presence of herpesviral antigen in the neurons. Rapid diagnosis of herpesviral encephalitis could be established in 2 hr. by examining FA-stained frozen sections. Two patients who had herpesviral encephalitis diagnosed by FA staining of brain biopsy sections were given treatment with an antiviral drug—idoxuridine.