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Home / Equine Research Bank / Virus Evol / Understanding the divergent evolution and epidemiology ...
Virus evolution2023; 9(2); vead052; doi: 10.1093/ve/vead052

Understanding the divergent evolution and epidemiology of H3N8 influenza viruses in dogs and horses.

Abstract: Cross-species virus transmission events can lead to dire public health emergencies in the form of epidemics and pandemics. One example in animals is the emergence of the H3N8 equine influenza virus (EIV), first isolated in 1963 in Miami, FL, USA, after emerging among horses in South America. In the early 21st century, the American lineage of EIV diverged into two 'Florida' clades that persist today, while an EIV transferred to dogs around 1999 and gave rise to the H3N8 canine influenza virus (CIV), first reported in 2004. Here, we compare CIV in dogs and EIV in horses to reveal their host-specific evolution, to determine the sources and connections between significant outbreaks, and to gain insight into the factors controlling their different evolutionary fates. H3N8 CIV only circulated in North America, was geographically restricted after the first few years, and went extinct in 2016. Of the two EIV Florida clades, clade 1 circulates widely and shows frequent transfers between the USA and South America, Europe and elsewhere, while clade 2 was globally distributed early after it emerged, but since about 2018 has only been detected in Central Asia. Any potential zoonotic threat of these viruses to humans can only be determined with an understanding of its natural history and evolution. Our comparative analysis of these three viral lineages reveals distinct patterns and rates of sequence variation yet with similar overall evolution between clades, suggesting epidemiological intervention strategies for possible eradication of H3N8 EIV.
© The Author(s) 2023. Published by Oxford University Press.
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Publication Date: 2023-08-18 PubMed ID: 37692894PubMed Central: PMC10484056DOI: 10.1093/ve/vead052Google Scholar: Lookup
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  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research examines how the H3N8 influenza virus, a type of flu that primarily affects horses and dogs, has evolved over time and spread across different geographical locations.

Introduction and Background

  • The study focuses on the H3N8 virus, which first emerged among horses in South America in 1963 and was later identified in Miami, FL, USA.
  • The virus had later transferred to dogs in 1999, and the first official case of the H3N8 canine influenza virus (CIV) was reported in 2004.
  • The researchers aimed to understand how this virus evolves differently in horses and dogs, and what factors influence these evolutionary paths.

Evolution of the H3N8 Virus

  • The American lineage of the H3N8 equine influenza virus (EIV) eventually split into two clades known as the ‘Florida’ clades, which are still present today.
  • The researchers found that the H3N8 CIV, after first emerging, showed geographical restriction and only circulated in North America. By 2016, it had become extinct.
  • On the other hand, EIV Florida clade 1 shows widespread circulation and frequent transfers between the USA and South America, Europe and other regions.
  • Florida clade 2 became globally distributed soon after it emerged, but since around 2018, it has only been detected in Central Asia.

Implications and Further Research Needed

  • Understanding the natural history and evolution of the H3N8 virus is pre-requisite to gauge any potential zoonotic threat – the transmission of the virus from animals to humans.
  • Analyzed data revealed distinct patterns and rates of sequence variation across viral lineages, displaying similar overall evolution between clades. This could inform epidemiological intervention strategies towards the possible extermination of the H3N8 EIV.
  • Further research is required to corroborate these results, confirm the current status and distribution of different clades, and ascertain the conditions influencing virus evolution.

Cite This Article

APA
Wasik BR, Rothschild E, Voorhees IEH, Reedy SE, Murcia PR, Pusterla N, Chambers TM, Goodman LB, Holmes EC, Kile JC, Parrish CR. (2023). Understanding the divergent evolution and epidemiology of H3N8 influenza viruses in dogs and horses. Virus Evol, 9(2), vead052. https://doi.org/10.1093/ve/vead052

Publication

Virus evolution
ISSN: 2057-1577
NlmUniqueID: 101664675
Country: England
Language: English
Volume: 9
Issue: 2
Pages: vead052
PII: vead052

Researcher Affiliations

Wasik, Brian R
  • Baker Institute for Animal Health, Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
Rothschild, Evin
  • Baker Institute for Animal Health, Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
Voorhees, Ian E H
  • Baker Institute for Animal Health, Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
Reedy, Stephanie E
  • Department of Veterinary Science, Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546, USA.
Murcia, Pablo R
  • MRC-University of Glasgow Centre for Virus Research, School of Infection and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G61 1QH, Scotland.
Pusterla, Nicola
  • Department of Medicine & Epidemiology, School Veterinary Medicine, University of California, Davis, CA 95616, USA.
Chambers, Thomas M
  • Department of Veterinary Science, Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546, USA.
Goodman, Laura B
  • Baker Institute for Animal Health, Department of Public and Ecosystems Health, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
Holmes, Edward C
  • Sydney Institute for Infectious Diseases, School of Medical Sciences, University of Sydney, Sydney, NSW 2006, Australia.
Kile, James C
  • Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA.
Parrish, Colin R
  • Baker Institute for Animal Health, Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.

Grant Funding

  • MC_UU_12014/9 / Medical Research Council

Conflict of Interest Statement

None declared.

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