Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2016 Jun 27:13:113.
doi: 10.1186/s12985-016-0565-8.

Differences in viral load among human respiratory syncytial virus genotypes in hospitalized children with severe acute respiratory infections in the Philippines

Francois Marie Ngako Kadji  1 , Michiko Okamoto  1 , Yuki Furuse  1 , Raita Tamaki  1 , Akira Suzuki  1 , Irene Lirio  2 , Clyde Dapat  1 , Rungnapa Malasao  1 , Mariko Saito  2 , Gay Anne Granada Pedrera-Rico  3 , Veronica Tallo  4 , Socorro Lupisan  4 , Mayuko Saito  5 , Hitoshi Oshitani  1
Affiliations

Differences in viral load among human respiratory syncytial virus genotypes in hospitalized children with severe acute respiratory infections in the Philippines

Francois Marie Ngako Kadji et al. Virol J. .

Abstract

Background: Human respiratory syncytial virus (HRSV) is a leading viral etiologic agent of pediatric lower respiratory infections, including bronchiolitis and pneumonia. Two antigenic subgroups, HRSV-A and B, each contain several genotypes. While viral load may vary among HRSV genotypes and affect the clinical course of disease, data are scarce regarding the actual differences among genotypes. Therefore, this study estimated and compared viral load among NA1 and ON1 genotypes of HRSV-A and BA9 of HRSV-B. ON1 is a newly emerged genotype with a 72-nucleotide duplication in the G gene as observed previously with BA genotypes in HRSV-B.

Findings: Children <5 years of age with an initial diagnosis of severe or very severe pneumonia at a hospital in the Philippines from September 2012 to December 2013 were enrolled. HRSV genotypes were determined and the viral load measured from nasopharyngeal swabs (NPS). The viral load of HRSV genotype NA1 were significantly higher than those of ON1 and BA9. Regression analysis showed that both genotype NA1 and younger age were significantly associated with high HRSV viral load.

Conclusions: The viral load of NA1 was higher than that of ON1 and BA9 in NPS samples. HRSV genotypes may be associated with HRSV viral load. The reasons and clinical impacts of these differences in viral load among HRSV genotypes require further evaluation.

Keywords: Children; Genotype; Pneumonia; Respiratory syncytial virus; Viral load.

PubMed Disclaimer

Figures

Fig. 1
Fig. 1
Quantitative PCR amplification of partial sequence (658 nucleotides) N genes of HRSV NA1, ON1 and BA9 genotypes. A dilution series of high-quality RNA copies was used to generate standard curves as describe in the methods. Reactions were performed in triplicate. HRSV genotypes Ct values stand for the cycle at which reporter fluorescence crosses the software-defined threshold. The linear range of threshold cycle vs RNA copies was (2 - 9) Log10 copies/μl. Solid line, linear regression of RNA copies vs Ct values. Dashed lines represent the 95 % confidence intervals for potential regression lines. The slopes and y-intercepts are -3.70, 44.35 for NA1, -3.77, 44.83 for ON1 and -3.74, 44.91 for BA9
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Borchers AT, Chang C, Gershwin ME, Gershwin LJ. Respiratory syncytial virus--a comprehensive review. Clin Rev Allergy Immunol. 2013;45:331–379. doi: 10.1007/s12016-013-8368-9. - DOI - PMC - PubMed
    1. Peret TC, Hall CB, Schnabel KC, Golub JA, Anderson LJ. Circulation patterns of genetically distinct group A and B strains of human respiratory syncytial virus in a community. J Gen Virol. 1998;79(Pt 9):2221–2229. doi: 10.1099/0022-1317-79-9-2221. - DOI - PubMed
    1. Venter M, Madhi SA, Tiemessen CT, Schoub BD. Genetic diversity and molecular epidemiology of respiratory syncytial virus over four consecutive seasons in South Africa: identification of new subgroup A and B genotypes. J Gen Virol. 2001;82:2117–2124. doi: 10.1099/0022-1317-82-9-2117. - DOI - PubMed
    1. Shobugawa Y, Saito R, Sano Y, Zaraket H, Suzuki Y, Kumaki A, Dapat I, Oguma T, Yamaguchi M, Suzuki H. Emerging genotypes of human respiratory syncytial virus subgroup A among patients in Japan. J Clin Microbiol. 2009;47:2475–2482. doi: 10.1128/JCM.00115-09. - DOI - PMC - PubMed
    1. Eshaghi A, Duvvuri VR, Lai R, Nadarajah JT, Li A, Patel SN, Low DE, Gubbay JB. Genetic variability of human respiratory syncytial virus A strains circulating in Ontario: a novel genotype with a 72 nucleotide G gene duplication. PLoS One. 2012;7:e32807. doi: 10.1371/journal.pone.0032807. - DOI - PMC - PubMed

Publication types