DETECTION OF RESPIRATORY SYNCYTIAL VIRUS, PARAINFLUENZAVIRUS-3, ADENOVIRUS AND RHINOVIRUS SEQUENCES IN RESPIRATORY-TRACT OF INFANTS BY POLYMERASE CHAIN-REACTION AND HYBRIDIZATION

Background: Immunofluorescence assay (IFA) of viral antigens in nasal aspirates is largely used for the diagnosis of respiratory syncytial v irus (RSV), parainfluenzavirus (PIV) type 3 and adenovirus (AdV) infec tions, whilst rhinovirus (RV) are detected by virus isolation techniqu e (VIT) only. Using the two techniques, IFA and VIT, a significant num ber of specimens remain negative in spite of clinical and epidemiologi cal presumptions of viral infection. Objectives and study design: The polymerase chain reaction (PCR) should improve the sensitivity of vira l detection in clinical specimens. From October 1995 to March 1996, 27 7 nasal aspirates from hospitalized infants were tested simultaneously by IFA, VIT, polymerase chain reaction and hybridization with a DNA e nzyme immunoassay (PCR-EIA) for RSV, PIV-3, AdV and RV. Results: RSV w ere detected in 177 (64%) samples, PIV-3 in 23 (8%), RV in 40 (14%), a nd AdV in 30 (10%). PCR-EIA detected RSV in more samples 173 (62%) tha n IFA/VIT: 109 (39%) (P < 10(-7)). In most cases (79%), RSV-infected i nfants had lower respiratory tract disease, and routine and PCR techni ques were positive. Out of the 23 PIV-3 infections, 12 were IFA/VIT- a nd PCR-EIA-positive, and 11 IFA/VIT-negative and PCR-EIA-positive. For RV, 35 (87%) specimens were PCR EIA-positive and 11 (27%) culture-pos itive; for AdV 30 samples were PCR-EIA-positive and four were culture- positive. Simultaneous viral infections were revealed in a significant ly higher proportion than in conventional techniques: 18% (50/277) ver sus 2.5% (7/277); P < 10(-7). One RSV infection in four was associated with the presence of another virus, mainly PIV-3 (16 cases) and AdV ( 13 cases). Conclusions: PCR-EIA detects more positive-specimens than I FA/VIT, 1.5 times more for RSV, 1.9 for PIV-3, 4 for RV and 10 for AdV , respectively. This increased sensitivity of viral detection by PCR-E IA compared to the IFA/VIT could suggest that samples containing low l evels of virus are missed by routine methods IFA/VIT, and consequently , RSV or PIV-3, and above all RV or AdV are overlooked as agents of re spiratory diseases. However, apart from the fact that the economic and convenient aspects of virus diagnostic cannot be missed, it is diffic ult to answer the following questions: what is the meaning of the dete ction of a viral sequences in nasal aspirates of infants,or may PCR ha ve detected virus in patients who would not developed disease? (C) 199 7 Elsevier Science B.V.