New Superbug Threat from Intensive Pig Farms

by 5m Editor
23 June 2011, at 11:35am

UK - The Soil Association is calling on the Government to take immediate action to limit the spread of a deadly new type of Salmonella, which is passing from pigs to humans.

Known as monophasic Salmonella typhimurium, it is has enhanced ability to cause infections and a particularly high attack rate in children and old people, leading to an unusually high rate of hospitalisation. It is also highly resistant to antibiotics, limiting treatment options.

Several different strains have already emerged and caused numerous infections in humans and at least one death. Professor John Trelfall from the Health Protection Agency has acknowledged that it appears "to be associated with pigs and pig products." German scientists have found clear evidence it is being transmitted from pigs to humans "along the food chain," and called for interventions at a farm level to prevent human infection.

The Soil Association wants a panel of experts to undertake an urgent review of the mounting evidence that specific action is needed to address the serious threat posed by the new type of Salmonella, and evidence that all Salmonella can spread directly from pigs to people, as well as via food. It also wants Caroline Spelman, Secretary of State for the Environment, to intervene and stop any new intensive pig farms being built near residential areas at least until the panel has made recommendations.

Planners in Derbyshire will shortly decide whether or not to approve one of the largest ever pig farms in the UK for the company Midland Pig Producers on the outskirts of the village of Foston, which would house 25,000 pigs. The Soil Association is staging an open meeting with Pig Business today for local residents concerned about the proposed development

Exact statistics on the number of cases in the UK are not available, but the Government’s main advisory committee on antibiotic resistance in animals has warned that it "appeared currently to be the most predominant type of Salmonella in Europe". The European Food Safety Authority has described its incidence as ‘epidemic’. The available evidence strongly suggests that it is increasing in pigs and humans in the UK. There have also been cases in British cattle.

Most monophasic salmonella from pigs are resistant to at least four families of antibiotics but the long-feared development of resistance to modern cephalosporin antibiotics in Salmonella has already been found as well on at least one British pig farm. The European Food Safety Authority has warned that resistance to these antibiotics could lead to treatment failures. They also warned that even the routine use of antibiotics such as tetracyclines, the most widely used antibiotics in pig feed, not only promotes resistance but also increases the spread and persistence in pigs of these resistant strains.

Flies and cockroaches are known to carry Salmonella and other pathogens found on pigs, and American scientists have said that because these insects can move freely between animal waste on farms and nearby houses there is an "increasing concern in the medical and public-health community about insect pests directly associated with the spread of bacterial pathogens and antibiotic-resistant microorganisms with animal production systems to residential settings". This is particularly significant because Dr Rob Davies from the Veterinary Laboratories Agency believes that monophasic Salmonella typhimurium may have the ability to be shed in large numbers in faeces compared with other strains. Flies were a particular problem on one of Midland Pig Producers' other pig farms when journalists visited it last year.

According to Dr Davies, monophasic Salmonella typhimurium is one of several Salmonella strains to have evolved in pigs. Furthermore, another very recently published government study found that 28 per cent of British pigs tested positive for Salmonella. Of these, 92 per cent of these showed resistance to antibiotics, with 67 per cent being multi-resistant. A British government survey in 2002 found that one in every 12 sausages (8.6 per cent) were contaminated with Salmonella.

Research has shown that pigs raised indoors excrete higher levels of Salmonella in their manure than do outdoor-raised pigs, both organic and non-organic. Many scientific studies also show that Salmonella in pigs increases with herd size.