Human metapneumovirus (MPV) (HMPV)

Human Metapneumovirus

Human metapneumovirus (MPV) (HMPV)

• is a respiratory pathogen with worldwide prevalence that produces disease clinically similar to respiratory syncytial virus (RSV)
  • like other members of the Paramyxovirus family, is an enveloped, single-stranded, negative-sense RNA virus
  • is most closely related to avian metapneumovirus type C, the other member of the Metapneumovirus genus, and it is in the Pneumovirinae subfamily with RSV
    • MPV is closely related to avian metapneumovirus subtype C, has circulated for at least 65 years, and nearly every child will be infected with HMPV by the age of 5 (2)
      
      
• is a leading cause of upper and lower respiratory tract infections in children
  • incubation period is believed to be 4 to 9 days
  • shedding occurs for 7 to 14 days
  • virus can remain infectious on fomites for 8 hours, although viral RNA has been isolated from noninfectious particles up to 7 days after inoculation (1)
    
  • a leading cause of acute respiratory infection, particularly in children, immunocompromised patients, and the elderly (2)
    • children with underlying risk factors including those born prematurely or who have compromised immune systems are at higher risk from MPV (3)
      • as with other viruses, infection may produce incomplete immunity and reinfection can occur at all ages
      • older adults, especially those over 65 or with underlying conditions, can be at particular risk from infection
        
        
• clinical features of MPV-associated disease are similar to those of RSV
  • MPV is an important cause of asthma exacerbations, bronchiolitis, and pneumonia
  • smptoms can include cough, rhinorrhea, sore throat, and fever as well as lower respiratory tract symptoms such as wheezing, difficulty breathing, and hypoxia (2)
  • bacterial superinfection can occur
  • clinical diagnoses most commonly associated with HMPV are bronchiolitis and pneumonia (2)
    
    
• mean age of infection is 6 to 12 months, and nearly all school-age children are seropositive (1)
  • however, infection can recur, likely in part due to impaired CD8+ T-cell response
  • is thought to spread through direct or close contact with infected individuals or objects (fomites) (2)
    
    
• preferred method for diagnosis is reverse transcription-polymerase chain reaction as HMPV is difficult to culture (2)
  
  
• morbidity and mortality are the highest in patients who are premature, are immunosuppressed, or have underlying cardiopulmonary abnormalities (1)

Reference:

1. Schuster JE, Williams JV. Human metapneumovirus. Pediatr Rev. 2013 Dec;34(12):558-65. doi: 10.1542/pir.34-12-558. PMID: 24295817; PMCID: PMC4531267.
2. Shafagati N, Williams J. Human metapneumovirus - what we know now. F1000Res. 2018 Feb 1;7:135. doi: 10.12688/f1000research.12625.1. PMID: 29744035; PMCID: PMC5795268.
3. Wise J. HMPV: the little known virus that’s making its mark in intensive care BMJ 2023; 381 :p1299 doi:10.1136/bmj.p1299