Prevalence and Risk Factors for Swine Influenza Virus Infection in the English Pig Population

17 November 2011, at 12:00am

There was evidence of the swine flu virus on half of the farms tested by a UK research group, and the likelihood of finding this evidence was lower for pigs kept in straw yards, during the summer and where there were fewer pigs per drinker.

Infection of pigs with influenza viruses is a cause of considerable economic loss for pig farmers as well as a potential human health concern – as evidenced by the identification of genetic material derived from swine-adapted influenza viruses in an novel strain of H1N1 influenza virus in 2009.

Alexander Mastin of the UK's Royal Veterinary College and co-authors there and at the University of Cambridge and Veterinary Laboratories Agency explain in their paper published in PLoS Currents earlier this year that they conducted an investigation into the prevalence of influenza virus infection in a selection of 143 English pig herds between April 2008 and April 2009.

They report that they found evidence of recent virus circulation in over half of these herds (n=75). Farms which were sampled in the summer months were found to have lower odds of recent virus circulation, as were farms containing pigs kept in straw yards. Additionally, farms containing pigs kept indoors and farms containing high numbers of finisher pigs per water space were found to have higher odds of recent virus circulation.

It is hoped that further studies will expand on these findings, and may allow targeting of surveillance for influenza viruses in the English pig population, concluded Mastin and his co-authors.


Mastin, A., P. Alarcon, D. Pfeiffer, J. Wood, S. Williamson, I. Brown and B. Wieland. 2011. Prevalence and risk factors for swine influenza virus infection in the English pig population. PLoS Curr. 3: RRN1209. doi: 10.1371/currents.RRN1209

Further Reading

- You can view the full report by clicking here.

Further Reading

- Find out more information on influenza in pigs by clicking here.

November 2011