Metapneumovirus

Metapneumovirus refers to a genus of enveloped, negative-sense RNA viruses in the family Pneumoviridae. It includes human metapneumovirus (HMPV), a common cause of respiratory infections in humans, and avian metapneumovirus (AMPV), which infects birds. The genus was established after the discovery of HMPV in 2001 in the Netherlands. HMPV and AMPV share structural features and replicate in the respiratory tract.

In humans, HMPV is a widespread pathogen responsible for a range of illnesses from mild upper respiratory tract infections to bronchiolitis and pneumonia, particularly in young children, older adults, and immunocompromised individuals. Transmission occurs through respiratory droplets, direct contact with contaminated surfaces, and possibly aerosols. Seasonal peaks typically occur in winter and spring in temperate climates, with year‑round activity in tropical regions.

Clinical presentation often includes cough, fever, nasal congestion, and wheezing; symptoms can last one to two weeks or longer in severe cases. Diagnosis is usually made by reverse-transcription PCR testing of nasopharyngeal or throat swabs; antigen tests are less sensitive, and culture or serology is used less frequently in routine practice.

There is no licensed vaccine for HMPV. Management is supportive, including hydration and oxygen therapy as needed; bronchodilators may be used for wheezing. Ribavirin and intravenous immunoglobulin have been reported in some severe or immunocompromised cases, but evidence is limited. Prevention relies on standard infection control practices such as hand hygiene and isolation of ill individuals.

Research on vaccines and targeted therapies is ongoing, with several candidates evaluated in clinical trials.