title: Epidemiologic characteristics and seasonal distribution of human metapneumovirus infections in five epidemic seasons in Stockholm, Sweden, 2002-2006.
abstract: The presence of human metapneumovirus (hMPV) was analyzed retrospectively by reverse transcriptase-polymerase chain reaction (RT-PCR) in five epidemic seasons, in Stockholm, 2002-2006. The occurrence of hMPV was compared with five common respiratory viruses; respiratory syncytial virus, influenza A virus, influenza B virus, parainfluenza virus and adenovirus. With a detection rate of 2.9% (n = 143/4,989) in nasopharyngeal samples over the whole period, hMPV was the fourth most common respiratory virus after RSV, influenza A and parainfluenza virus. hMPV genotype A dominated over genotype B, out of 91 genotyped virus samples 87 belonged to genotype A and four belonged to genotype B. Approximately 50.3% (n = 72/143) of the hMPV positive patients were <3 years, 49.7% (71/143) were > or =3 years and 38,5% (n = 55/143) were <1 year. The relative frequencies of hMPV infections in the three age groups were 2.8% (72/2,579), 2.9% (71/2,410) and 2.6% (55/2,122), respectively. This age distribution differed from RSV, influenza A, B and parainfluenza virus. hMPV epidemics peaked in March, not coincident with RSV or parainfluenza virus. In successive epidemic seasons, large outbreaks of hMPV alternated with small outbreaks in a regular, biannual pattern. Large hMPV virus epidemics were anticyclical to large RSV epidemics. It is concluded that the epidemiology of hMPV differs markedly from other common respiratory viruses.
authors.affiliation: Division of Clinical Microbiology, Karolinska University Hospital, Karolinska Institute, Stockholm, Sweden.
authors.forename: Farideh
authors.initials: F
authors.lastname: Rafiefard
authors.forename: Zhibing
authors.initials: Z
authors.lastname: Yun
authors.forename: Claes
authors.initials: C
authors.lastname: Orvell
mesh_terms: D000257:Adenoviridae Infections / Q000453:epidemiology; D000367:Age Factors; D004196:Disease Outbreaks; D005838:Genotype; D006801:Humans; D007251:Influenza, Human / Q000453:epidemiology / Q000821:virology; D029121:Metapneumovirus / Q000145:classification* / Q000302:isolation & purification*; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D009305:Nasopharynx / Q000821:virology; D018184:Paramyxoviridae Infections / Q000453:epidemiology* / Q000821:virology*; D015995:Prevalence; D012367:RNA, Viral / Q000235:genetics / Q000302:isolation & purification; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology / Q000821:virology; D012189:Retrospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012621:Seasons; D017422:Sequence Analysis, DNA; D013548:Sweden / Q000453:epidemiology
chemical_list: D012367:RNA, Viral