Human Metapneumovirus and Lower Respiratory Tract Disease in Otherwise Healthy Infants and Children

In a large, prospective study of children with lower respiratory tract illness, human metapneumovirus was identified in 49 of 248 specimens (20 percent) that were negative for other pathogenic viruses. The mean age of the infected children was 11.6 months, and 59 percent had symptoms of bronchiolitis. This virus was isolated only rarely from asymptomatic children. A large study shows that human metapneumovirus is a leading cause of respiratory tract infection in young children. Respiratory syncytial virus (RSV), parainfluenza virus, adenovirus, and influenzavirus are common known causes of lower respiratory tract disease in infants and children. 1 – 3 Nevertheless, in a substantial portion of lower respiratory tract infections in children, no virus can be cultured. In 2001, researchers in the Netherlands isolated a new virus from children and adults with acute respiratory tract infection. 4 This RNA virus, provisionally designated human metapneumovirus, is closely related to avian pneumovirus. Since then, investigators in Canada, Australia, the United Kingdom, and the United States have described patients with acute respiratory tract infection due to human metapneumovirus. 5 – 8 We sought . . .