RSV Classification

RSV is a 15 kb negative sense single stranded RNA virus encoding 11 proteins1,2

hMPV: Human Metapneumovirus; RSV: Respiratory Syncytial Virus.

    1. Kolli D, Velayutham, TS, Casola, A. Pathogen. 2013;1;2(2):232-263.
    2. MacLachlan, NJ, Dubovi, EJ. Fenner’s Veterinary Virology (5th ed.). 2016; pp. 328-356.
    3. Taxonomy History - Taxonomy - ICTV (ictvonline.org)

History of RSV

Humans and chimpanzees are the only known natural hosts for human RSV, although a variety of small animal species may be experimentally infected with RSV (Calves, Ferrets, Rodents)2. Currently, there is no known RSV reservoir in the off-season5.

RSV is one of the last major causes of serious paediatric infections for which no vaccine or other wide-scale intervention is available1

FDA: Food and Drug Administration; RSV: Respiratory Syncytial Virus.

    1. Domachowske JB et al, Pediatr Infect Dis J. 2004 Nov;23(11 Suppl):S228-34. doi: 10.1097/01.inf.0000144672.81955.a4.
    2. Vincent JL, et al. Acute Parenchymal Disease in Pediatric Patients. 2017.
    3. Morris J et al Proc Soc Exp Biol Med, 92 (1956), pp. 544-549
    4. Chanock R et al Am J Hyg, 66 (1957), pp. 281-290
    5. Collins PL et al ,J Virol. 2008 Mar;82(5):2040-55. doi: 10.1128/JVI.01625-07. Epub 2007 Oct 10

RSV is classified into two subtypes – RSV-A and RSV-B; based on variation in the G protein1

  • RSV-A and -B diverged in 17664
  • RSV-A and RSV-B co-circulate
  • Dominance shift between RSV-A and RSV-B types every 1-2 years2
  • There are no significant differences in severity between RSV-A and B2

RSV-A

  • 9-16 distinct genotypes(GA1-GA7, SAA1, NA1-4 and ON1)3,5

RSV-B

  • 22-32 distinct genotypes(BA1-14, GB1-GB5, SAB1-4, URU1-2, NZB1-2, BA-CCA, BA-CCB, BA-C, CBB and CB)4,5

No consensus on RSV genotype definition6

Appearance of RSV-A and RSV-B genotypes and dominance over time (1961–2014)1

    1. Hause AM, et al. PLOS One. 2017;12(6).
    2. Ciarlitto C. et al. Italian Journal of Pediatrics. 2019;45.
    3. Global RSV surveillance. WHO: www.who.int/teams/global-influenza-programme/global-respiratory-syncytial-virus-surveillance/laboratory-testing. Accessed 12 May 2022.
    4. Saito M et al, Viruses. 2021 Dec 15;13(12):2525. doi: 10.3390/v13122525. PMID: 34960794; PMCID: PMC8706373.
    5. Yu, JM et al. Sci Rep 11, 12941 (2021). https://doi.org/10.1038/s41598-021-92435-1
    6. Chen J et al. Influenza Other Respir Viruses. 2022 May;16(3):492-500. doi: 10.1111/irv.12936. Epub 2021 Dec 10. PMID: 34894077; PMCID: PMC8983899.

RSV Genome and Morphology

  • RSV is an enveloped, medium-sized (120 to 300 nm) RNA virus2
  • Nonsegmented, single-stranded, negative-sense genome2
  • The viral envelope has a bilipid layer derived from the plasma membrane of the host cells2
  • Its surface has transmembrane surface glycoprotein spikes 11 to 12 nm in length and 6 to 10 nm apart2
  • The 10 viral genes are depicted by the divided bars2
  • Each viral gene transcribes a single messenger RNA (mRNA) encoding a single protein, with the exception of M2 mRNA, which transcribes two proteins, M2-1 and M2-22

NS1: non-structural protein 1; NS2: non-structural protein 2; ssRNA: single stranded ribonucleic acid; RSV: Respiratory Syncytial Virus.

    1. Battles MB, McLellan, JS. Nature Reviews Microbiology. 2019;17:233–245.
    2. Walsh EE et al ,Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases (Eighth Edition), 2015, https://doi.org/10.1016/B978-1-4557-4801-3.00160-0.
    3. Pandya MC et al. Pathogens. 2019 May 21;8(2):67. doi: 10.3390/pathogens8020067. PMID: 31117229 PMCID: PMC6631838.
    4. Kinear E et al https://www.immunology.org/public-information/bitesized-immunology/pathogens-and-disease/respiratory-syncytial-virus-rsv Electron micrograph image credit to Prof. Roberto Garofalo, UTMB

MAT-BH-2300310-V1-April-2023