Respiratory syncytial virus epidemic periods in an equatorial city of Brazil

Abstract

BackgroundCharacterization of the human respiratory syncytial virus (HRSV) season at the local level has important implications for appropriate decisions on the time period for administration of specific prophylaxis.Objectives(1) To describe five consecutive epidemic periods of HRSV in an equatorial city of Brazil and (2) to show preliminary data on genomic diversity of circulating HRSV.Patients/MethodsNasopharyngeal aspirates of 2885 children attending the emergency room and wards of a public hospital were collected and screened by indirect immunofluorescence for HRSV infections during five consecutive years (from January 2004 to December 2008). In addition, the genetic and antigenic variability of the HRSV strains isolated was evaluated by partial nucleotide sequencing of the protein G gene.Results HRSV was detected in 15·8% of the analyzed samples. HRSV seasons occurred in a restricted period of each year. The onset of each HRSV season was variable (February to May), but the end always occurred in July. From the 456 HRSV infections found, 86 cases with bronchiolitis were genotyped. Both HRSV subgroups (A and B) cocirculated during the five epidemic periods. The 58 HRSV‐A strains grouped into two clades, GA2 and GA5. In respect of the HRSV‐B strains, the 28 samples grouped into two clades: GB3 and BA.Conclusions HRSV accounts for a substantial proportion of ARI in the study population. As in temperate countries, HRSV infections in this equatorial area of Brazil also cause seasonal yearly epidemics, and this has implications for prophylaxis strategies. The city of Fortaleza follows the same worldwide trend of circulation of genotypes of HRSV.

Adenoviruses and acute respiratory infections in children living in an equatorial area of Brazil

“…The main climate change during the year in Fortaleza is the rainy season. Previous studies have demonstrated an association between the rainy season and epidemic periods of RSV and influenza, but this did not occur with HAdVs in our study [32,33]. In addition, the correlation between the occurrence of the PIV-3 and the dry season, reported in other studies [32,34], was not observed with HAdVs, even though the detection rates of these viruses were highest in the dry months of September and October.…”

Spatial‐temporal distribution and sequence diversity of group a human respiratory syncytial viruses in Kenya preceding the emergence of ON1 genotype

“…Our findings relate to other studies that have reported dominance of GA2 and NA1 genotypes coinciding with our study seasons: studies conducted in Belgium (2006–2011), 35 Madrid (2007–2014), Panama (2010–2012), 5 and another in Kenya covering thirteen seasons from 2000 to 2012 9 . A study conducted in Brazil showed replacement of GA5 genotype with GA2 genotype during 2005–2008 seasons 36 . This is an interesting shift in contrast to pre‐millennium reports in which the HRSVA genotypes were shown to co‐circulate with variation in genotype dominance and especially from mid 1970s–2000s 4,5 .…”

“… 9 A study conducted in Brazil showed replacement of GA5 genotype with GA2 genotype during 2005–2008 seasons. 36 This is an interesting shift in contrast to pre‐millennium reports in which the HRSVA genotypes were shown to co‐circulate with variation in genotype dominance and especially from mid 1970s–2000s. 4 , 5 The millennium studies have reported a shift from multiple genotype circulation to replacement of an existing genotype and its increased dominance.…”

Relative frequency, Possible Risk Factors, Viral Codetection Rates, and Seasonality of Respiratory Syncytial Virus Among Children With Lower Respiratory Tract Infection in Northeastern Brazil

“…[7][8][9][10][11][12][13][14][15][16] Some studies conducted in Brazil have suggested a clear seasonal pattern for RSV infections, with predominance from March to July, and a smaller number of cases in the summer months, especially November to February. [14][15][16][17][18][19] Other viruses have been investigated to a lesser extent, but a seasonal pattern was found for different respiratory viruses in Southern and Southeastern Brazil, where the winter is cold and dry. 10,13,20 Only a few studies were conducted to investigate the prevalence and seasonal patterns of different viral infections among children with an episode of LRTI seen at hospitals from Northeastern Brazil, where the winter is warm and wet.…”