Background
Human metapneumovirus (hMPV) was first described in 2001 by researchers in the Netherlands. Using polymerase chain reaction (PCR) amplification techniques, the virus was isolated from stored nasopharyngeal samples [1].

hMPV, like human respiratory syncytial virus (RSV), is classified in the Pneumovirinae subfamily of the Paramyxoviridae family; genetically, hMPV is most closely related to avian metapneumovirus. It’s been hypothesized that hMPV originated in birds, but the serological evidence shows that hMPV has been widespread and active from at least 1958. Determining the origin of hMPV has proven difficult [1, 2].

Epidemiology
hMPV is the second leading identifiable cause of lower respiratory tract disease in children and is known to cause disease in all age groups. hMPV infection likely accounts for up to 10% of hospitalizations for pediatric respiratory illnesses [1, 3].

Risk factors for severe hMPV disease appear to be similar to those for severe RSV disease and include prematurity, heart or pulmonary disease, immunocompromised status, and organ transplant [1, 4].

Initial hMPV infection occurs early in childhood, with most individuals seroconverting by age 5 years. The seropositivity rate approaches 100% by age 10 years [1, 4, 5].

Treatment
No specific antiviral therapy is available for hMPV infection. Treatment includes routine symptomatic care with respiratory support when required.

Ribavirin, which has broad antiviral activity, has been shown to have activity against hMPV in vitro [6].

Diagnosis
The clinical symptoms are similar to those seen with RSV infection and may also include high fever, myalgia, rhinorrhea, dyspnea, tachypnea, and wheezing. Hospitalization, supplemental oxygen, and mechanical ventilation may be necessary in severe hMPV infections [1, 7].

Real-time RT-PCR has been described previously as a valuable tool for rapid detection of hMPV RNA [8].

References

  1. van den Hoogen BG, de Jong JC, Groen J et al. (2001) A newly discovered human pneumovirus isolated from young children with respiratory tract disease. Nat Med 7(6):719–724.
  2. Feuillet F, Lina B, Rosa-Calatrava M et al. (2012) Ten years of human metapneumovirus research. J Clin Virol 53(2):97–105.
  3. Pelletier G, Déry P, Abed Y et al. (2002) Respiratory tract reinfections by the new human Metapneumovirus in an immunocompromised child. Emerg Infect Dis 8(9):976–978.
  4. Boivin G, Abed Y, Pelletier G et al. (2002) Virological features and clinical manifestations associated with human metapneumovirus: a new paramyxovirus responsible for acute respiratory-tract infections in all age groups. J Infect Dis 186(9):1330–1334.
  5. Leung J, Esper F, Weibel C et al. (2005) Seroepidemiology of human metapneumovirus (hMPV) on the basis of a novel enzyme-linked immunosorbent assay utilizing hMPV fusion protein expressed in recombinant vesicular stomatitis virus. J Clin Microbiol 43(3):1213–1219.
  6. Wyde PR, Chetty SN, Jewell AM et al. (2003) Comparison of the inhibition of human metapneumovirus and respiratory syncytial virus by ribavirin and immune serum globulin in vitro. Antiviral Res 60(1):51–59.
  7. Schildgen O, Geikowski T, Glatzel T et al. (2005) Frequency of human metapneumovirus in the upper respiratory tract of children with symptoms of an acute otitis media. Eur J Pediatr 164(6):400–401.
  8. Maertzdorf J, Wang CK, Brown JB et al. (2004) Real-time reverse transcriptase PCR assay for detection of human metapneumoviruses from all known genetic lineages. J Clin Microbiol 42(3):981–986.