Serologic Response of Individuals Infected with Para Influenza Viruses

Abstract

An evaluation of the hemagglutination inhibition and neutralization technics revealed them to be sensitive serologic procedures for the diagnosis of infection by para influenza 1 and 3 viruses. Complement fixation proved to be a sensitive method for serodiagnosis of para influenza 3 infection but not for para influenza 1 infection unless the associated illness was of a severe nature. Etiologic diagnosis by serologic means was hampered by the occurrence of heterotypic responses, which were more commonly observed following para influenza 1 infection. Of the two methods examined for such heterotypic responses, the hemagglutination inhibition technic was preferable to the complement-fixation procedure, since the latter test tended to underestimate the occurrence of para influenza 1 infection and to overestimate para influenza 3 infection. In view of the 20% heterotypic response rate observed in the hemagglutination inhibition test, it would appear that specific etiologic diagnosis can best be established by virus isolation.