Makin' Bacon - pork production carries high cost to environment and health

E: The Environmental Magazine, May, 2000 by Becky Gillette

Pork Production Is Linked to the Risk of Flu Epidemics and Infections

Bacon in the morning may still smell great, but eating pork raises concerns about more than just the impact of all that fat and cholesterol on your arteries. Recent research indicates the "other white meat" is a passageway for a number of serious illnesses, which can jump from animals to human hosts. And the intensive, factory farm conditions by which most pigs are raised increases the risk and acts as an incubator for bacteria. There's also proof, for the first time, that using antibiotics to treat pigs can lead to outbreaks of dangerous human diseases like salmonella.

Scientists say there is a link between swine and the spread of influenza (flu), which kills about 20,000 people in the U.S. annually. Pigs pick up the flu virus from wild aquatic birds, and pass it on to humans through their breakfast sausages or ham sandwich.

"Transmission of influenza viruses from birds to mammals has probably occurred for centuries," said Dr. Robert Webster of the St. Jude Children's Research Hospital, Memphis, Tennessee, speaking at the Second International Symposium on Influenza and Other Respiratory Viruses. "However, increased opportunities for transmission, larger chicken and pig populations, and overall growth of human populations are associated with a higher risk of interspecies reassortment. This situation is a possible start for a new pandemic."

While the timing of the next influenza pandemic cannot be predicted, experts agree it is inevitable. The U.S. Centers for Disease Control and Prevention (CDC) projects that the next pandemic could kill between 89,000 and 207,000 people, and result in 314,000 to 734,000 hospitalizations. Infectious disease specialists say health authorities are not prepared.

The CDC estimates that 80 percent of deaths from flu can be prevented with a flu shot. But in the event of a pandemic, it would take about 22 weeks to develop and manufacture a new vaccine. This timeline could be trimmed to 12 weeks if the potential vaccine candidate is already present in a "library" of potential pandemic strains.

Even so, Webster says, "The time frame to create the vaccine and produce sufficient numbers of doses are major obstacles to a rapid response. This pandemic will potentially be associated with major problems in detection, prevention, vaccine production, drug manufacture and distribution," according to Webster. "The breakout will also be associated with major political and social problems, without easy answers. Active international surveillance and improvement of international communication, new progress in vaccine production, funding of specific research and new surveillance networks and collaboration with drug companies are vital to address the coming pandemic."

A Smoking Gun?

Other health problems are also associated with swine production. In Malaysia, more than 250 people, mostly pig farm workers, developed encephalitis after exposure last year to swine infected with the Nipah virus (which is believed to be spread by fruit bats). More than 100 of those people died. A million pigs have been slaughtered in an effort to control the virus, which was still infecting farmers as late as last January.

A 1999 Danish study published in The New England Journal of Medicine links the common practice of feeding livestock low levels of antibiotics to multidrug-resistant salmonella infections in humans. Dr. Bryan White, a University of Illinois animal scientist, calls the study "a smoking gun" that definitively establishes a link between feeding subtherapeutic levels of antibiotics and development of bacteria in the meat that can be transmitted to people. In the Danish case, 25 people who ate meat from swine herds were infected with a rare strain of drug-resistant salmonella. Eleven people were hospitalized and two died.

White says other studies had shown a suspected link between feeding antibiotics to livestock and subsequent infection, but the Danish research was the first iron-clad study. "This study tells me what I already knew: You can get human pathogens with antibiotic resistance," says white. "A lot of outbreaks we thought were not linked to antibiotic use in livestock might be. It is my opinion that it would be prudent for farmers to discontinue feeding subtherapeutic levels of antibiotics. The European community has banned use of all these antibiotics in feed now. They are well ahead of the U.S."

Antibiotics are routinely fed to livestock in the United States to promote growth. But White argues that with good management practices, farmers could get the same growth response from animals in the absence of antibiotics in feed. Last February, Congressman Sherrod Brown (D-OH) introduced H.R. 3266, a bill that would require animal drug manufacturers to prove to the Food and Drug Administration (FDA) that there is "reasonable certainty" of no human harm from their antibiotics. "The FDA is dragging its feet on this issue" says the Union of Concerned Scientists' Lara Levison, "proposing a complicated regulatory framework that would deal only with future approvals of antibiotics, ignoring those that are already in use."