title: Human metapneumovirus associated with respiratory tract infections in a 3-year study of nasal swabs from infants in Italy.
abstract: The newly described human metapneumovirus (hMPV) is reported here to be more commonly associated with lower respiratory tract disease. The present study examined nasal swab specimens from 90 infants with acute respiratory tract infections in Pisa, Italy, over a period of three respiratory virus seasons. The incidence of infection varied in each of the 3 years, with the rates of positivity for hMPV being 7% in 2001 but 37 and 43% in 2000 and 2002, respectively. hMPV was noted to occur seasonally in a pattern typical of the frequency of occurrence of respiratory syncytial virus. More than one-half (14 of 23) of the infants infected with hMPV had bronchopneumonia. One-third (9 of 23) of the hMPV-infected patients were also infected with another respiratory virus, a relationship that has not previously been reported. Mixed infections did not account for a higher percentage of cases of bronchopneumonia than hMPV infection alone did. Furthermore, 7 of 17 infants whose plasma was also tested for hMPV RNA were demonstrated to have virus in both nasal swab and blood specimens. The study indicates that hMPV is seen as commonly as other respiratory viruses, may be associated with severe respiratory disease in infants, can establish mixed infections with other respiratory viruses, and has a seasonal occurrence.
authors.affiliation: Virology Section, Department of Experimental Pathology, University of Pisa, Pisa, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Maggi
authors.forename: Massimo
authors.initials: M
authors.lastname: Pifferi
authors.forename: Marialinda
authors.initials: M
authors.lastname: Vatteroni
authors.forename: Claudia
authors.initials: C
authors.lastname: Fornai
authors.forename: Elena
authors.initials: E
authors.lastname: Tempestini
authors.forename: Silvia
authors.initials: S
authors.lastname: Anzilotti
authors.forename: Letizia
authors.initials: L
authors.lastname: Lanini
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Andreoli
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Ragazzo
authors.forename: Mauro
authors.initials: M
authors.lastname: Pistello
authors.forename: Steven
authors.initials: S
authors.lastname: Specter
authors.forename: Mauro
authors.initials: M
authors.lastname: Bendinelli
mesh_terms: D000208:Acute Disease; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D007558:Italy / Q000453:epidemiology; D029121:Metapneumovirus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D009305:Nasopharynx / Q000382:microbiology*; D018184:Paramyxoviridae Infections / Q000453:epidemiology* / Q000821:virology; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012367:RNA, Viral / Q000097:blood; D012141:Respiratory Tract Infections / Q000453:epidemiology* / Q000821:virology; D012621:Seasons; D017422:Sequence Analysis, DNA; D013048:Specimen Handling / Q000379:methods*
chemical_list: D012367:RNA, Viral