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A recent article on 'Swine Influenza and Factory Farming' produced by CIWF suggested a link to human health from farming pigs in unnatural and inhumane conditions. ADAS Senior Animal Health & Welfare Consultant David Moorhouse discusses the facts and some possible solutions.

The article ‘Swine Influenza and Factory Farming’ produced by CIWF [http://www.ciwf.org.uk/swineflu_report_050509 ] suggests a link to human health from “farming pigs in unnatural and inhumane conditions”. In particular they assert that scientists have been warning for years that influenza viruses originating in pigs pose a real risk to human health as they are capable of making a “species jump” to humans and becoming a global pandemic.

However, current information suggests that while the new variant human influenza virus which has infected people in the U.S., Mexico and other parts of the world may have originated in pigs, there is currently no evidence that it is circulating in pigs. It has proved to be highly contagious between humans (as is normal human influenza) although not highly pathogenic (disease causing) at this stage.

The United Kingdom and some other forward looking members of the European Union undertake routine surveillance to help detect the presence of animal diseases not normally present in the European Union and to identify any change at an early stage in the prevalence of diseases that do occur. The Veterinary Laboratories Agency has run a national swine influenza surveillance programme since 1991. Funded by Defra and the Scottish government this provides free-of-charge laboratory testing for the detection of swine influenza viruses in clinical samples from affected pigs submitted by veterinary surgeons. Results of the surveillance suggest that this variant of H1N1 does not appear currently to be present in pigs in the United Kingdom or anywhere else in the European Union.

Influenza viruses circulating within humans have the potential to transmit to pigs because the virus contains avian, swine and human elements. However the first known human-to-pig infection of the new flu virus A (H1N1) at a pig farm in Canada, apparently after being infected by a farm worker who recently returned from Mexico, does not boost the chances of the pathogen mutating or becoming more virulent (Source: Bernard Vallat, director general of the World Organisation for Animal Health). The herd, in the western province of Alberta, had tested positive for Mexican influenza, with up to 200 pigs at the farm infected with the virus, scientifically known as 2009 H1N1. The infection was not severe and was followed by recovery in both man and pigs, demonstrating it is n...