The farming of living creatures for maximised profit inevitably leads to the overcrowding found in intensive rearing, which in turn results in stress leading to disease which is normally kept under control by veterinary intervention. We have recently had cause to focus on intensive salmon farming here in Orkney, as licences are being sought for huge installations up to 10 times the size of the small established farm sites already in existence. A recent article in the scientific press has concentrated on intensive pig farming. 6 million pigs died, mostly by the farmer's hand rather than the virus. Fears are growing that Europe's crowded barns might be a breeding ground for human as well as animal disease.
Evidence exists that pigs can breed new strains of influenza which humans can catch.
The existence of influenza in pigs is closely correlated with the density of pigs in farms. Recent epidemics have struck at chickens, cattle and rabbits, but worst of all at pigs. For farming economic efficiency, pigs are born on one farm, weaned on another and fattened on a third. In these specialised institutions thousands of animals are crammed together, all from different places. These are the ideal conditions for explosive outbreaks of disease and traditional measures such as herd slaughter and bans on transport of animals are unable to prevent contagion.