Human Metapneumovirus as a Major Cause of Human Respiratory Tract Disease

Abstract

Human metapneumovirus (hMPV) is a newly identified paramyxovirus that appears to be one of the most significant and common viral infections in humans. The virus, first isolated in 2001, is a clear cause of lower respiratory tract disease in both the very young and the frail elderly. The virus causes acute wheezing in children or, less commonly, croup or pneumonia. Molecular epidemiology studies have shown that field strains exhibit sufficient sequence diversity to designate 2 subgroups of circulating viruses. Small animal and nonhuman primate models of infection have been described, which will allow studies of pathogenesis and immunity. Recombinant viruses have already been generated by several groups using reverse genetics, which facilitates the study of the biology of the virus and the generation of live attenuated vaccine candidates. Ongoing research promises to elucidate the molecular basis for pathogenesis and immunity of human metapneumovirus infections and to pave the way for rapid vaccine development.