Reassortant Pandemic (H1N1) 2009 Virus in Pigs | CDC EID

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Volume 17, Number 6–June 2011
Dispatch
Reassortant Pandemic (H1N1) 2009 Virus in Pigs, United Kingdom
Wendy A. Howard, Steve C. Essen, Benjamin W. Strugnell, Christine Russell, Laura Barrass, Scott M. Reid, and Ian H. Brown
Author affiliations: Veterinary Laboratories Agency–Weybridge, Addlestone, UK (W.A. Howard, S.C. Essen, C. Russell, L. Barrass, S.M. Reid, I.H. Brown); and Veterinary Laboratories Agency–Thirsk, Thirsk, UK (B.W. Strugnell)


Suggested citation for this article


Abstract
Surveillance for influenza virus in pigs in the United Kingdom during spring 2010 detected a novel reassortant influenza virus. This virus had genes encoding internal proteins from pandemic (H1N1) 2009 virus and hemagglutinin and neuraminidase genes from swine influenza virus (H1N2). Our results demonstrate processes contributing to influenza virus heterogeneity.
During the 1918 influenza pandemic, the virus likely passed from humans to pigs (1).

Descendants of this virus (classical swine influenza viruses), first isolated in 1930 (2), have continued to circulate in pigs (1). Other influenza viruses have caused either sporadic or enzootic infections.

Until 2009, the predominant influenza virus subtypes in pigs in Europe were avian-like (H1N1), human-like (H3N2) (representing virus transmissions from birds and humans, respectively), and H1N2 (3). Subtype H1N2 viruses, first identified in the United Kingdom in 1994 and subsequently detected throughout Europe, arose by reassortment between human subtype H1N1 (hemagglutinin [HA] gene), human-like swine subtype H3N2 (neuraminidase [NA] gene), and avian-like swine subtype H1N1 viruses (internal gene segments; 4,5).

Classical swine influenza viruses (H1N1) were dominant in North America (6). However, during the 1990s, infection of pigs with human subtype H3N2 virus resulted in viruses containing a triple-reassortant group of internal genes. These viruses contain genes derived from human, classical swine, and avian-origin viruses and can accept different HA and NA genes (6).

Pandemic (H1N1) 2009 virus is a reassortant virus with genes from recent North American triple reassortant (basic polymerase 2 [PB2], PB1, acidic polymerase, HA, nucleoprotein [NP], nonstructural gene) and European avian-like subtype H1N1 (NA, matrix [M]) viruses (7). Infections of domestic pigs with pandemic (H1N1) 2009 virus have been detected worldwide. In January 2010, a reassortant virus that contained a pandemic (H1N1) 2009 virus NA gene and an avian-like subtype H1N1 HA gene was detected in pigs in Hong Kong (8). This reassortant was efficiently transmitted between pigs (8). We report detection and characterization of a novel swine reassortant virus in the United Kingdom that has genes encoding internal proteins from pandemic (H1N1) 2009 virus and HA and NA genes from a swine subtype H1N2 virus.

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Reassortant Pandemic (H1N1) 2009 Virus in Pigs | CDC EID



Suggested Citation for this Article
Howard WA, Essen SC, Strugnell BW, Russell C, Barrass L, Reid SM, et al. Reassortant pandemic (H1N1) 2009 virus in pigs, United Kingdom. Emerg Infect Dis [serial on the Internet]. 2011 Jun [date cited]. http://www.cdc.gov/EID/content/17/6/1049.htm

DOI: 10.3201/eid1706.101886


Comments to the Authors
Please use the form below to submit correspondence to the authors or contact them at the following address:

Ian H. Brown, Department of Virology, Veterinary Laboratories Agency-Weybridge, Addlestone, Surrey KT15 3NB, UK; email: i.h.brown@vla.defra.gsi.gov.uk