But whether or not a direct link to the Smithfield facility is ever established, this pandemic reminds us that the current method of raising farm animals is fraught with risks to human health. In 1998, a virus that combined strains of human, swine, and bird flu was discovered in pigs at industrial operations in North Carolina. It rapidly mutated, or "reassorted," as it moved from pig to pig and from herd to herd. Within months, the hybrid virus was showing up in hog operations throughout the United States.
By early 1999, blood samples of pigs from 23 states showed that 20.5 percent had been exposed, according to Dr. Michael Greger, author of the book Bird Flu. "It is from this pool of viruses," Greger writes, "that the current swine flu threat derives three-quarters of its genetic material." Dr. Robert Webster, a leading flu expert and a director of the WHO Collaborating Center for Studies on the Ecology of Influenza in Animals and Birds, says that this "triple reassortment virus" is the likely precursor to the swine flu that is now sweeping the globe.
Pigs in the United States have become "an increasingly important reservoir of viruses with human pandemic potential," according to Dr. Richard Webby, also a director of the WHO Collaborating Center. One in five US pig workers now shows antibodies to H1N1, showing they have been exposed to the virus.
This is to be expected. My husband and I, as livestock ranchers ourselves and advocates of reform in industrial farming, have visited dozens of industrial animal operations. We've seen commercial swine operations with tens of thousands or even hundreds of thousands of pigs. And we've visited chicken operations with hundreds of thousands or millions of birds. These are typical operations. Extreme crowding and barren surroundings stress the animals, rendering them effective disease vehicles and making their environments conducive to the formation of new diseases. Lack of genetic diversity within flocks and herds renders them more susceptible to illnesses. Large populations of flies and insects aid in disease transmission.
"Industrial farm animal production facilities that house large numbers of animals in very close quarters can be a source of new or more infectious agents," the Pew Commission on Industrial Animal Production warned in April 2008. Ellen Silbergeld, professor at Johns Hopkins School of Public Health, says of industrial animal operations, "For many years, there's been a great deal of concern about their potential contribution to the evolution and spread of newly emerging diseases."
Dr. Silbergeld identifies three primary factors: crowding, ventilation systems that spread pathogens to the surrounding environment, and massive volumes of manure. It is "astounding," she says, that there are no requirements for any waste treatment applied to these huge animal operations--as, of course, there are for human sewage.