Breeding Grounds

Per capita meat consumption in China (FAO)

In response to the torrent of emerging and re-emerging zoonotic diseases jumping from animals to people, the world’s three leading authorities—the Food and Agriculture Organization of the United Nations, the World Health Organization, and the World Organization for Animal Health (OIE)—held a joint consultation in 2004 to determine the key underlying causes. Four main risk factors for the emergence and spread of these new diseases were identified. Bulleted first: “Increasing demand for animal protein.”⁹⁵¹ This has led to what the Centers for Disease Control refer to as “the intensification of food-animal production,” the factor blamed in part for the increasing threat.⁹⁵²

Animals were domesticated 10,000 years ago, but never like this. Chickens used to run around the barnyard on small farms. Now, “broiler” chickens—those raised for meat—are typically warehoused in long sheds confining an average of 20,000 to 25,000 birds.⁹⁵³ A single corporation, Tyson, churns out more than 20 million pounds of chicken meat a day.⁹⁵⁴ Worldwide, an estimated 70% to 80% of egg-laying chickens are intensively confined in battery cages,⁹⁵⁵ small barren wire enclosures stacked several tiers high and extending down long rows in windowless sheds.⁹⁵⁶ It is not uncommon for egg producers to keep hundreds of thousands—or even a million—hens confined on a single farm.⁹⁵⁷ Half the world’s pig population—now approaching 1 billion—is also crowded into industrial confinement operations.⁹⁵⁸ This represents the most profound alteration of the animal-human relationship in 10,000 years.⁹⁵⁹

Driven by the population explosion, urbanization, and increasing incomes,⁹⁶¹ the per-capita consumption of meat, eggs, and dairy products has skyrocketed in the developing world,⁹⁶² leading to a veritable Livestock Revolution beginning in the 1970s, akin to the 1960s Green Revolution in cereal grain production.⁹⁶³ World meat production has risen more than 500% over the past few decades.⁹⁶⁴ To meet the growing demand, livestock production will have to double by 2020.⁹⁶⁵

To evaluate the global risks of infectious animal diseases, the Iowa-based, industry-funded⁹⁶⁶ Council for Agricultural Science and Technology created a task force that included public health experts from the WHO, veterinary experts from the OIE, agriculture experts from the USDA, and industry experts from the likes of the National Pork Board. Its report was released in 2005 and traced the history of livestock production from family-based farms to industrial confinement. Traditional systems are being replaced by intensive systems at a rate of more than 4% a year, particularly in Asia, Africa, and South America. “A major impact of modern intensive production systems,” the report reads, “is that they allow the rapid selection and amplification of pathogens that arise from a virulent ancestor (frequently by subtle mutation), thus there is increasing risk for disease entrance and/or dissemination.” Modern animal agriculture provides “significant efficiency in terms of economy of scale,” but the “cost of increased efficiency” is increased disease risk. “Stated simply,” the report concluded, “because of the Livestock Revolution, global risks of disease are increasing.”⁹⁶⁷

In the United States, the average numbers of animals on chicken, pig, and cattle operations approximately doubled between 1978 and 1992.⁹⁶⁸ This increasing population density seems to be playing a key role in triggering emerging epidemics. In terms of disease control, according to the FAO, “[t]he critical issue is the keeping [of] more and more animals in smaller and smaller spaces….”⁹⁶⁹ The unnaturally high concentration of animals confined indoors in a limited airspace producing enormous quantities of manure provides, from a microbiologist’s perspective, “ideal conditions for infectious diseases.”⁹⁷⁰