From the Guidelines
Human Metapneumovirus (HMPV) is believed to have originated from birds, specifically from avian metapneumovirus type C, approximately 200-300 years ago. The virus was first discovered in 2001 in the Netherlands by researchers at the Erasmus Medical Center in Rotterdam, who isolated it from respiratory samples of young children with respiratory tract infections 1. Despite its relatively recent discovery, serological evidence suggests that HMPV has been circulating in human populations for at least 50 years prior to its identification. Some key points about HMPV include:
- It is a paramyxovirus closely related to RSV, causing increases in URTID and tracheobronchitis in 5%–20% of children and adults during winter 1
- HMPV infection is commonly diagnosed by NAT, and rates range from 2.5% to 9% during the first 2 years after allogeneic HSCT 1
- The virus underwent genetic changes that allowed it to cross the species barrier from birds to humans, adapting to efficiently infect and spread among human hosts. HMPV is now recognized as a common cause of respiratory infections worldwide, particularly in young children, the elderly, and immunocompromised individuals, causing symptoms similar to those of respiratory syncytial virus (RSV) including cough, fever, nasal congestion, and sometimes more severe lower respiratory tract infections.
From the Research
Origin of Human Metapneumovirus
- The origin of Human Metapneumovirus (HMPV) is closely related to avian metapneumovirus subtype C, suggesting a zoonotic transfer from birds to humans 2.
- Studies have shown that HMPV has been circulating in humans for at least 50 years, with serological evidence indicating human infection since 1958 or earlier 3.
- The virus is believed to have evolved from avian metapneumovirus subtype C (AMPV-C) following zoonotic transfer, with AMPV-C being more closely related to HMPV than to any other AMPV subgroup 2.
Global Distribution and Prevalence
- HMPV has been isolated from individuals with acute respiratory tract infections (ARTIs) in virtually every continent, indicating a global distribution 3.
- The virus is a common pathogen that can cause both upper and lower respiratory tract infections, particularly in children, elderly adults, and immunocompromised hosts 3, 4, 5, 6.
- HMPV is estimated to be responsible for about 5% to 10% of hospitalizations of children suffering from acute respiratory tract infections 5.
Epidemiology and Transmission
- HMPV has a seasonal variation, circulating in late winter to early spring in temperate climates and late spring and summer in tropical regions 3.
- The virus can cause severe bronchiolitis and pneumonia in children, and its symptoms are indistinguishable from those caused by human respiratory syncytial virus 5.
- Initial infection with HMPV usually occurs during early childhood, but re-infections are common throughout life 5, 6.