Human Metapneumovirus Pediatric Respiratory Infections: Comparing Direct Immunofluorescence versus Polymerase Chain Reaction

Estimated as the second or third most prevalent respiratory pathogen in the pediatric population, routine testing for human metapneumovirus (hMPV) can have a pivotal impact on children’s clinical outcome.
This cross-sectional analytical study aimed to determine the efficiency of direct fluorescent antibody (DFA) assay as a rapid tool for the diagnosis of hMPV infection as compared to real time reverse transcriptase polymerase chain reaction (rRT-PCR). In the meantime, we endeavored to analyze the clinical features in hMPV patients.
A total of 50 children aged ≤ 24 months presenting with manifestations of acute respiratory tract infection (ARTI) at El-Mounira pediatric university hospital, Cairo university were enrolled in the study. Nasopharyngeal aspirates (or endotracheal aspirates in intubated children) were examined with the DFA assay as well as rRT-PCR as a gold standard for the detection and quantification of hMPV.
Results and Human MPV was detected in two cases by DFA and in four cases by rRT-PCR among hospitalized children with ARTIs. The DFA assay proved to be a highly specific test, yet with low sensitivity when compared to rRT-PCR. Most of hMPV-infected cases presented during the winter season, with January and February exhibiting the highest hMPV activity. Pneumonia was the most common presentation of ARTIs in hMPV-infected patients. Direct evaluation of respiratory specimens by DFA provides rapid results with low cost and a subsequent early medical management. However, its use should be restricted as a first-line approach, and a confirmatory test would be needed for a definite diagnosis.