ABSTRACT
We aimed to validate a direct immunofluorescence assay (DFA) for the detection of human metapneumovirus (hMPV) from nasal swabs and to determine the incidence and clinical features of this viral infection in a pediatric population. One hundred twenty-one of 3026 nasal swabs were positive for hMPV by DFA (4.0%). Compared with reverse transcriptase polymerase chain reaction, the sensitivity and specificity of DFA were 90%, and 100%, respectively. Compared with RSV, hMPV infection was more common in children with congenital abnormalities, particularly those with cardio-pulmonary dysplasia and was associated with an increased ventilatory requirement.
Subject(s)
Fluorescent Antibody Technique, Direct/methods , Metapneumovirus/isolation & purification , Paramyxoviridae Infections/diagnosis , Paramyxoviridae Infections/epidemiology , Respiratory Syncytial Virus Infections/epidemiology , Adolescent , Child , Child, Preschool , Female , Humans , Incidence , Infant , Male , Nasal Cavity/virology , Paramyxoviridae Infections/pathology , Paramyxoviridae Infections/physiopathology , Respiratory Syncytial Virus Infections/pathology , Respiratory Syncytial Virus Infections/physiopathology , Reverse Transcriptase Polymerase Chain Reaction , Sensitivity and SpecificityABSTRACT
Although the human parainfluenza virus 4 (HPIV4) has been known for a long time, its genome, alone among the human paramyxoviruses, has not been completely sequenced to date. In this study we obtained the first complete genomic sequence of HPIV4 from a clinical isolate named SKPIV4 obtained at the Hospital for Sick Children in Toronto (Ontario, Canada). The coding regions for the N, P/V, M, F and HN proteins show very high identities (95% to 97%) with previously available partial sequences for HPIV4B. The sequence for the L protein and the non-coding regions represent new information. A surprising feature of the genome is its length, more than 17 kb, making it the longest genome within the genus Rubulavirus, although the length is well within the known range of 15 kb to 19 kb for the subfamily Paramyxovirinae. The availability of a complete genomic sequence will facilitate investigations on a respiratory virus that is still not completely characterized.
ABSTRACT
BACKGROUND: Institutional pandemic planning prompted a study of the molecular detection of influenza virus from respiratory specimens in children, compared to conventional diagnostics. OBJECTIVE: To evaluate the performance of a commercial qualitative real-time RT-PCR kit (rRT-PCR), the artus Influenza LC RT-PCR (Qiagen). STUDY DESIGN (METHODS): Specimens were pre-selected to include a high percentage of positives by direct immunofluorescence assay (DFA) or culture. The sensitivity and specificity of the kit for detection of influenza A and B in children were determined against the gold standard, DFA and culture. Specimens yielding discordant results between artus and the gold standard were tested against a reference rRT-PCR assay (Centers for Disease Control) to create an "expanded gold standard". RESULTS: When compared to DFA or cell culture, the sensitivity of the rRT-PCR artus kit was 96.2% and the specificity was 94%. It detected influenza RNA in 6.0% of clinical samples negative by DFA or culture. Using the expanded gold standard, the revised sensitivity was 98.7% (98.6% for influenza A and 97.6% for influenza B) and the specificity was 100%. CONCLUSION: The artus Influenza LC RT-PCR kit is an effective alternative to virus isolation and DFA for the detection of influenza A and B in pediatric clinical specimens.
