Human metapneumovirus (HMPV)
المؤلف:
Baijayantimala Mishra
المصدر:
Textbook of Medical Virology
الجزء والصفحة:
2nd Edition , p170-171
2025-10-19
99
Human metapneumovirus (HMPV) was first discovered in 2001 while isolating the possible viral pathogen from respiratory samples of infected children on monkey kidney cell line which produced cytopathic effect similar to respiratory syncytial virus (RSV) but nucleotide sequence similarity was found to be close to avian metapneumovirus (AMPV).
According to the recent ICTV, HMPV is a member of the genus Metapneumovirus in the family Pneumoviridae.
GENETIC DIVERSITY
HMPV has been divided into two major groups A and B based on the sequence variability of M, N, P, F and L genes. Each of the A and B groups or genetic lineages is further divided into sublineages A1, A2 and B1 and B2 based on the sequence identity of F and G proteins. Co-circulation of all the four lineages has been reported worldwide.
EPIDEMIOLOGY
Approximately 10% of all respiratory viral infections in children requiring hospitalizations are due to HMPV, whereas in adults it is responsible for 4–5% of severe respiratory disease.
HMPV infection can occur in all age groups but more common in children below 5 years age. First infection usually occurs around 6 months of age, after which there may be several repeated infections. As compared to RSV, older children are infected with HMPV. Elderly sick patients are the second common group of patients in whom HMPV can cause severe infection.
Seasonal peaks are observed with HMPV infection with a peak during cold winter months from December to February. The peak season of HMPV usually occurs after 1–2 months after RSV season.
CLINICAL FEATURES
Incubation period of HMPV infection is 4–6 days. In children, HMPV usually affects upper respiratory tract manifesting as fever, cough and rhinorrhea. Lower respiratory tract illness due to HMPV usually manifests as that of RSV with bronchiolitis, pneumonia, croup and acute exacerbation of asthma.
In healthy adults, HMPV generally produces mild symptoms, such as cough, sore throat, congestion, rhinorrhea and constitutional symptoms.
Severe lower respiratory tract illness due to HMPV can be seen in individuals with under lying chest diseases or immunocompromised patients and old adults with comorbid conditions. Up to 40% pneumonia has been reported in HMPV infection.
Coinfections of HMPV with RSV have been reported by some groups to cause more severe infection as compared to single infection. However, there is no consensus so far regarding this information.
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