Detection of human metapneumo virus among infants with bronchiolitis

Abstract

Human metapneumo virus (hMPV) is a major cause of lower respiratory tract infections in infants, elderly and immune-compromised patients. It is the second viral etiological agent, after RSV, which causes respiratory tract infections (RTI) in children, especially children below 5 years old. hMPV isolation in cell culture is trypsin-dependent and requires long incubation times, and untypical cell lines. Antibody responses have not been useful in the diagnoses of acute hMPV infections. Commercial kits for detection of hMPV antigens by monoclonal antibodies in clinical samples have become available, promoting the rapid detection of the virus. The present study aimed to detect human metapneumo virus in infants with suspected viral chest infection and compare direct fluorescent (DFA) with nested RT-PCR assay in detection of the virus. Subjects and methods: This study included 30 children <18 months presented to pediatric emergency room of Ain Shams University Children's Hospital diagnosed clinically as cases of bronchiolitis. Nasopharyngeal aspirates were collected and transferred to the lab on calf bovine serum to be examined by Direct Immune-Fluorescence (DFA) for presence of hMPV antigen and nested-RT PCR for detection of hMPV genome. Results: Six out of thirty samples included in the study were positive for hMPV antigen by DFA and three out of thirty were positive for hMPV gene by RT-PCR assay with 100 % sensitivity and 89% specificity for DFA. Conclusion: Human metapneumo virus infection is a leading cause of respiratory tract infection in Infants; DFA can be used as a primary and easy diagnostic test for detection of hMPV in those infants.