September 10, 2012
The H3N2v influenza virus continues to spread. The U.S. Centers for Disease Control and Prevention (CDC) announced on Friday that the strain has infected at least 297 people so far this year (up from 12 in 2011). At least one person, a 61-year-old woman in Ohio, has died as a result. The agency has also confirmed that H3N2v is spreading between humans, not just from pigs to fairgoers.
This is cause for concern. Viruses evolve quickly, and the public health community has feared for many years that an influenza virus circulating in non-human hosts will jump to humans and spread rapidly among us. This is what happened in 2009 when an H1N1 influenza strain jumped from pigs to humans, infecting at least 1.6 million people and killing at least 19,000 worldwide. There is no indication yet that H3N2v will do the same, but the CDC and state health departments are monitoring the situation closely.
CLF’s director, Dr. Robert S. Lawrence, recently penned an article for TheAtlantic.com on how industrial food animal production (IFAP) increases the risk of pandemic influenza. To recap: When viruses infect cells and reproduce, their genes can change both through mutations and by the reassortment of genes from other viruses that infect the same cell. As viruses infect and reproduce more often, genetic changes occur more frequently. Some changes advantage the reproduction and spread of the viruses in which they occur, and these viruses outcompete others to become the dominant strains in circulation.
The concentration of thousands and sometimes millions of poultry or swine at IFAP sites is a good example of this. With so many animals, influenza viruses have ample opportunity to infect and reproduce, and some viruses may acquire the ability to infect humans. IFAP workers are in near-constant contact with these animals throughout the workday and human infectivity could advantage such viruses by allowing them to infect these human hosts. IFAP workers may then serve as “bridge populations” that can spread influenza viruses from IFAP sites to surrounding communities and beyond.
To reduce the probability of an influenza pandemic, we should reconsider the industrial model by which the majority of food animals in this country are produced. It is often claimed by the food animal industry that this model has resulted in unprecedented efficiency—animal protein appears to be cheaper than ever before. But the prices of meat, dairy, and eggs in the grocery store do not capture the true cost of how these commodities are generated; they do not include the massive public health and environmental costs externalized by the industry and thus foisted upon the larger society.
Influenza is one example of this. CDC researchers estimated that another influenza pandemic, more deadly than H1N1 in 2009, could cost $71-166 billion in the U.S alone. Another example is antimicrobial resistance (AMR), to which IFAP is an important contributor. It has been estimated that AMR increases U.S. health care spending by as much as $26 billion each year. Neither influenza nor AMR is solely attributable to IFAP, of course, but IFAP contributes to both and should be remembered when industry groups argue that meat is cheap.