Human metapneumovirus (HMPV) is a newly described virus in the family Paramyxoviridae. The virus was first reported as a cause of respiratory illness in children in 2001. The clinical manifestations of HMPV are closely similar to that of RSV infection in children. Human metapneumovirus like other members of the family Paramyxoviridae is a single-stranded RNA virus. The virus is a respiratory pathogen and is associ-ated as the cause of respiratory tract disease in children and adults worldwide.
The virus appears to be prevalent worldwide. The first report of virus in 2001 demonstrated that all Dutch children by the age of 10 years were seropositive for the virus. Similar studies conducted in Australia, Canada, Japan, and Israel have shown the high seroprevalence of HMPV antibodies in the population. Infants, elderly persons, and immunocompromised individuals appear to be more susceptible to infection by the virus.
The virus is an important cause of respiratory tract infec-tion in children, particularly in infants. It causes a disease, clinical manifestations of which are very much similar to those caused by human RSV. It causes a clinical disease, which ranges from mild respiratory symptoms to severe cough, bronchiolitis, and pneumonia. The condition is also associ-ated with high-grade fever, vomiting, and myalgia. The virus also causes RSV-like diseases in adults, especially in those with chronic obstructive lung disease.
The virus is very difficult to grow in cell culture, and cur-rently, serodiagnosis tests are not widely available for diagnosis of the condition. PCR appears to be the most specific test for diagnosis of the condition by examination of respiratory secre-tions. These include nasopharyngeal swabs, nasopharyngeal aspirates, or bronchoalveolar lavage specimens.
No specific antiviral treatment is available for HMPV infection. Hence, the treatment is majorly supportive. No vaccine is currently available for HMPV infection. Characteristics of various genera in the family Paramyxoviridae are summarized in Table 62-2.