title: Seasonal patterns of viral and bacterial infections among children hospitalized with community-acquired pneumonia in a tropical region.
abstract: Community-acquired pneumonia (CAP) is a common cause of morbidity among children. Evidence on seasonality, especially on the frequency of viral and bacterial causative agents is scarce; such information may be useful in an era of changing climate conditions worldwide. To analyze the frequency of distinct infections, meteorological indicators and seasons in children hospitalized for CAP in Salvador, Brazil, nasopharyngeal aspirate and blood were collected from 184 patients aged < 5 y over a 21-month period. Fourteen microbes were investigated and 144 (78%) cases had the aetiology established. Significant differences were found in air temperature between spring and summer (p = 0.02) or winter (p < 0.001), summer and fall (p = 0.007) or winter (p < 0.001), fall and winter (p = 0.002), and on precipitation between spring and fall (p = 0.01). Correlations were found between: overall viral infections and relative humidity (p = 0.006; r = 0.6) or precipitation (p = 0.03; r = 0.5), parainfluenza and precipitation (p = 0.02; r = -0.5), respiratory syncytial virus (RSV) and air temperature (p = 0.048; r = -0.4) or precipitation (p = 0.045; r = 0.4), adenovirus and precipitation (p = 0.02; r = 0.5), pneumococcus and air temperature (p = 0.04; r = -0.4), and Chlamydia trachomatis and relative humidity (p = 0.02; r = -0.5). The frequency of parainfluenza infection was highest during spring (32.1%; p = 0.005) and that of RSV infection was highest in the fall (36.4%; p < 0.001). Correlations at regular strength were found between several microbes and meteorological indicators. Parainfluenza and RSV presented marked seasonal patterns.
authors.affiliation: Paediatrics Department, Federal University of Bahia School of Medicine, Salvador, Brazil. nascimentocarvalho@hotmail.com
authors.forename: Cristiana M
authors.initials: CM
authors.lastname: Nascimento-Carvalho
authors.forename: Maria-Regina A
authors.initials: MR
authors.lastname: Cardoso
authors.forename: Aldina
authors.initials: A
authors.lastname: Barral
authors.forename: César A
authors.initials: CA
authors.lastname: Araújo-Neto
authors.forename: Juliana R
authors.initials: JR
authors.lastname: Oliveira
authors.forename: Luciana S
authors.initials: LS
authors.lastname: Sobral
authors.forename: Annika
authors.initials: A
authors.lastname: Saukkoriipi
authors.forename: Mika
authors.initials: M
authors.lastname: Paldanius
authors.forename: Raija
authors.initials: R
authors.lastname: Vainionpää
authors.forename: Maija
authors.initials: M
authors.lastname: Leinonen
authors.forename: Olli
authors.initials: O
authors.lastname: Ruuskanen
mesh_terms: D001419:Bacteria / Q000145:classification* / Q000302:isolation & purification; D001769:Blood / Q000382:microbiology / Q000821:virology; D001938:Brazil / Q000453:epidemiology; D002675:Child, Preschool; D017714:Community-Acquired Infections / Q000453:epidemiology* / Q000382:microbiology / Q000821:virology; D005260:Female; D006801:Humans; D006813:Humidity; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009305:Nasopharynx / Q000382:microbiology / Q000821:virology; D018410:Pneumonia, Bacterial / Q000453:epidemiology* / Q000382:microbiology; D011024:Pneumonia, Viral / Q000453:epidemiology* / Q000382:microbiology; D015995:Prevalence; D011891:Rain; D012621:Seasons; D013696:Temperature; D014329:Tropical Climate; D014780:Viruses / Q000145:classification* / Q000302:isolation & purification