Human Metapneumovirus Infection

1. Alexandra Vinci, MD* 2. Paul J. Lee, MD*,† 3. Leonard R. Krilov, MD*,† 1. *Children’s Medical Center, NYU Winthrop Hospital, Mineola, NY. 2. †State University of New York, Stony Brook School of Medicine, Stony Brook, NY. Human metapneumovirus (HMPV) is a frequent cause of upper and lower respiratory tract infections in children, immunocompromised patients, and adults. A lipid-enveloped, negative-sense, single-stranded RNA virus, HMPV is a member of the Paramyxoviridae family, which also includes respiratory syncytial virus (RSV) and the parainfluenza viruses. Since its discovery in the Netherlands in 2001 it has been found worldwide, with humans serving as its primary source of infection. It is spread by direct or close contact with infected secretions. Primates other than humans, such as macaque monkeys, develop signs and symptoms of disease after infection with HMPV. Although infection has not resulted from inoculation of HMPV in birds, there is an avian metapneumovirus subtype that commonly infects bird species. HMPV is composed of genetic groups A and B, which are divided further into 4 subclasses: A1, A2, B1, and B2. Most individuals have been infected by 5 years of age; however, following early infection, immunity to HMPV is weak and does not confer protection from the virus over a lifetime. No …