Serological diagnosis of parainfluenza virus infections: verification of the sensitivity and specificity of the haemagglutination-inhibition (HI), complement-fixation (CF), immunofluorescence (IFA) tests and enzyme immunoassay (ELISA).

Using four serological tests paired sera were examined of 117 patients with acute respiratory diseases, in whom parainfluenza viruses (PIV) infection was demonstrated by virus isolation, and of 41 patients with typical clinical mumps symptoms. Comparative analysis showed the high sensitivity of IFA and ELISA. A significant rise of antibodies in convalescent sera with homologous antigen of PIV was found in nearly 100 percent of cases. Only the sera of youngest children with high titres of persisting maternal antibodies remained without seroconversion. Cross heterologous antibody responses could be found by means of ELISA in 45% and by IFA in 10%, of patients who in the past experienced infection with one or more PIV or mumps virus--apart from homologous antibody reaction. HI and CF test proved to be less sensitive for detection of postinfections antibodies, especially in primoinfections with PIV types 1 and 2.