Human Metapneumovirus

Descriptive text is not available for this imageBASICS

Discovered in 2001, human metapneumovirus (hMPV) is an ubiquitous virus that is a common cause of upper and lower respiratory tract infections.

EPIDEMIOLOGY

  • Humans are the only source for infection.
  • Typically (prior to SARS-CoV-2 era) circulates during late winter and early spring, with onset beginning after respiratory syncytial virus (RSV) season
  • Most infections occur by 5 years of age.
  • Incubation: 4 to 9 days
  • Transmission occurs via direct contact with contaminated secretions, through person-to-person contact, and contact with contaminated objects.

Prevalence

  • Average prevalence of infection is 5–10%, although may be much higher during peak circulation.
  • Leading cause of upper and lower respiratory tract infection, second only to RSV in prevalence

ETIOLOGY

hMPV is an enveloped single-stranded, negative-sense RNA virus in the genus Metapneumovirus of the family Pneumoviridae.

RISK FACTORS

  • Younger age, especially the 1st year of life, associated with more severe disease and need for hospitalization
  • Prematurity and underlying medical conditions are risk factors for hospitalization.
  • Lower respiratory tract disease most common among young children, the elderly, and immunocompromised hosts

GENERAL PREVENTION

  • No vaccine available
  • Strict infection prevention measures needed for hospitalized children
  • Contact precautions and strict hand washing

PATHOPHYSIOLOGY

  • Virus inoculates nasopharyngeal mucosa and spreads to respiratory tract.
  • Attaches through glycoprotein (G) and enters through the fusion (F) protein into the host cells; the viral nucleocapsid then undergoes replication in the cytoplasm.
  • The fusion (F) and attachment (G) surface glycoproteins determine the major antigenic lineages.
  • Produces mucus hyperproduction and hyperplasia of respiratory epithelium

COMMONLY ASSOCIATED CONDITIONS

  • Upper respiratory tract disease
  • Bronchiolitis
  • Pneumonia
  • Croup
  • Asthma exacerbation
  • Otitis media

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