• Using molecular techniques, human Metapneumovirus (hMPV) was identified in 2001 as a respiratory virus associated with illness in children.
• A member of the Pneumoviridae family. Originally classified as a subfamily within the Paramyxoviridae family, in 2016, it was reclassified as a separate family containing 2 genera, Metapneumovirus (hMPV) and Orthopneumovirus (RSV).
• This virus is a large, enveloped, negative sense, single-stranded RNA virus.
• Worldwide distribution; in the USA, circulation is primarily winter through spring.
• A ubiquitous organism, such that by 5 years of age most children will have experienced an infection and test seropositive.
• Transmission occurs by contact with respiratory secretions and large particle aerosols.
• Responsible for approximately 15% of “colds” in young children.
• The virus replicates in respiratory epithelial cells.
• No specific features distinguish infection by HMPV from other viral respiratory illnesses.
- The average incubation period is 5-6 days with illness lasting approximately a week.
- Infection with hMPV tends to be asymptomatic, but may cause upper and lower respiratory illness in patients of all ages.
- cough, sore throat, runny nose, and high fever
- Less frequently, in more severe cases wheezing, dyspnea, pneumonia, bronchitis, or bronchiolitis may occur
- Symptomatic disease most often occurs in the very young, older adults and immunocompromised patients.
• Respiratory samples (nasopharyngeal swab, nasal wash or bronchial wash): Identification of hMPV is by PCR, usually as part of a multiplex respiratory pathogen panel.
• Cell culture is not useful, as hMPV is very difficult to grow in vitro.
• Serology: generally not commercially available, and most are seropositive by age 5.
• Other respiratory viruses (adenovirus, influenza, parainfluenza, RSV)
• There is no specific antiviral treatment for hMPV; medical care is supportive.
Prevention and Control:
• Prevent contact with infectious respiratory secretions by following good hand hygiene and respiratory etiquette.
• Clean surfaces that may be contaminated with infectious respiratory secretions.