Diagnosis and epidemiological studies of human metapneumovirus using real-time PCR.

BACKGROUND: Human metapneumovirus (hMPV) is prevalent in children, the elderly and immunocompromised individuals, but available epidemiological data is limited. OBJECTIVES: (1) To develop and validate a real-time PCR method for hMPV diagnosis. (2) To determine the percentage of hMPV in respiratory specimens from the community and its association with outbreaks in our geographic area. (3) To provide epidemiological data in terms of age distribution, seasonality and co-infections. STUDY DESIGN: A real-time PCR assay was designed for detection of hMPV lineages A and B. Prospective testing for hMPV over a 22-month period was then undertaken. RESULTS: The real-time PCR was sensitive and specific for detection of both lineages of hMPV. hMPV was detected in 9.5% (n=8239) of the specimens and 25% of the outbreaks (n=100) tested. The hMPV-positive patients ranged in age from 18 days to 99 years with a median age of 24 months. The number of positive samples peaked during the winter months of December, January and February. A high rate of co-infections was noted in the samples tested. CONCLUSIONS: hMPV is common in the community and is associated with outbreaks. Including hMPV in routine testing improves etiological diagnosis of acute respiratory infections.