Epidemiology and genetic variability of respiratory syncytial virus in Portugal, 2014-2018.

Respiratory syncytial virus (RSV) is associated with substantial morbidity and mortality since it is a predominant viral agent causing respiratory tract infections in infants, young children and the elderly. Considering the availability of the RSV vaccines in the coming years, molecular understanding in RSV is necessary. The objective of the present study was to describe RSV epidemiology and genotype variability in Portugal during the 2014/15-2017/18 period. Epidemiological data and RSV-positive samples from patients with a respiratory infection were collected through the non-sentinel and sentinel influenza surveillance system (ISS). RSV detection, subtyping in A and B, and sequencing of the second hypervariable region (HVR2) of G gene were performed by molecular methods. Phylogenetic trees were generated using the Neighbor-Joining method and p-distance model on MEGA 7.0. RSV prevalence varied between the sentinel (2.5%, 97/3891) and the non-sentinel ISS (20.7%, 3138/16779), being higher (P < 0.0001) among children aged <5 years. Bronchiolitis (62.9%, 183/291) and influenza-like illness (24.6%, 14/57) were associated (P < 0.0001) with RSV laboratory confirmation among children aged <6 months and adults ≥65 years, respectively. The HVR2 was sequenced for 562 samples. RSV-A (46.4%, 261/562) and RSV-B (53.6%, 301/562) strains clustered mainly to ON1 (89.2%, 233/261) and BA9 (92%, 277/301) genotypes, respectively, although NA1 and BA10 were also present until 2015/2016. The sequence and phylogenetic analysis reflected the relatively high diversity of Portuguese RSV strains. BA9 and ON1 genotypes, which have been circulating in Portugal since 2010/2011 and 2011/2012 respectively, predominated during the whole study period.

Sáez-López E ，Cristóvão P ，Costa I ，Pechirra P ，Conde P ，Guiomar R ，Portuguese Laboratory Network for the Diagnosis of Influenza Infection ，Peres MJ ，Viseu R ，Lopes P ，Soares V ，Vale F ，Fonseca P ，Freitas L ，Alves J ，Pessanha MA ，Toscano C ，Mota-Vieira L ，Veloso RC ，Côrte-Real R ，Branquinho P ，Pereira-Vaz J ，Rodrigues F ，Cunha M ，Martins L ，Mota P ，Couto AR ，Bruges-Armas J ，Almeida S ，Rodrigues D ... -  《-》

Predominance of ON1 and BA9 genotypes of respiratory syncytial virus (RSV) in Bulgaria, 2016-2018.

The objectives of this study were to investigate the prevalence of respiratory syncytial virus (RSV) infections in Bulgaria, to characterize the genetic diversity of the RSV strains, and to perform amino acid sequence analysis of the RSV G protein. Clinical, epidemiological data and nasopharyngeal swabs were prospectively collected from children aged less than 5 years presenting with acute respiratory infections from October 2016 to September 2018. Real-time polymerase chain reaction for 12 respiratory viruses, and sequencing, phylogenetic, and amino acid analyses of the RSV G gene/protein were performed. Of the 875 children examined, 645 (73.7%) were positive for at least one viral respiratory pathogen. RSV was the most commonly detected virus (26.2%), followed by rhinoviruses (15%), influenza A (H3N2) (9.7%), adenoviruses (9%), bocaviruses (7.2%), human metapneumovirus (6.1%), parainfluenza viruses 1/2/3 (5.8%), influenza type B (5.5%), and A(H1N1)pdm09 (3.4%). The detection rate for RSV varied across two winter seasons (36.7% vs 20.3%). RSV-B cases outnumbered those of the RSV-A throughout the study period. RSV was the most common virus detected in patients with bronchiolitis (45.1%) and pneumonia (24%). Phylogenetic analysis indicated that all the sequenced RSV-A strains belonged to the ON1 genotype and the RSV-B strains were classified as BA9 genotype. Amino acid substitutions at 15 and 22 positions of the HVR-2 were identified compared with the ON1 and BA prototype strains, respectively. This study revealed the leading role of RSV as a causative agent of serious respiratory illnesses in early childhood, year-on-year fluctuations in RSV incidence, the dominance of RSV-B, and relatively low genetic diversity in the circulating RSV strains.

Korsun N ，Angelova S ，Trifonova I ，Voleva S ，Grigorova I ，Tzotcheva I ，Mileva S ，Alexiev I ，Perenovska P ... -  《-》

Genetic characterization of respiratory syncytial virus highlights a new BA genotype and emergence of the ON1 genotype in Lyon, France, between 2010 and 2014.

Respiratory syncytial virus (RSV) is a well-recognized cause of respiratory tract infections. Based on G gene variations, 11 RSV-A and 36 RSV-B genotypes have been described to date. The ON1 genotype was detected in Ontario in 2010 and subsequently reported in several countries. The objective of the present study was to investigate for the first time the RSV epidemiology and genotype diversity in France between 2010 and 2014. All respiratory samples received from patients with influenza-like illness or respiratory tract infection were screened for RSV infection by RT-PCR. The results were stratified according to winter season. Among the RSV-positive cases, 117 samples were further investigated for phylogenetic analysis out of 150 randomly selected for sequencing. Among the 20,359 cases screened, 14% of the cases were RSV-positive. RSV-A was predominant during the four winter seasons. The first ON1 variant was detected during the 2010-2011 winter and reached 85% of all RSV-A-positive cases in 2013-2014. Most RSV-B was classified as BA9 and BA10 genotypes but a new genotype (BA-Ly) was described. As reported in different countries, ON1 variants were firstly detected in 2011 and became the predominant RSV-A genotype in Lyon. Among RSV-B, BA9 was predominant but detected alongside BA10 or a transient genotype (BA-Ly).

Gaymard A ，Bouscambert-Duchamp M ，Pichon M ，Frobert E ，Vallee J ，Lina B ，Casalegno JS ，Morfin F ... -  《-》

[Epidemiologic characteristics and the relationship with disease severity of respiratory syncytial virus genotypes from children with lower respiratory tract infection in the southern Zhejiang province].

Dong L ，Dai L ，Fan J ，Chen X ，Jin X ，Zhang Y ，Lin H ... -  《-》

Prevalence and genetic characterisation of respiratory syncytial viruses circulating in Bulgaria during the 2014/15 and 2015/16 winter seasons.

Korsun N ，Angelova S ，Tzotcheva I ，Georgieva I ，Lazova S ，Parina S ，Alexiev I ，Perenovska P ... -  《-》