Scott Hurd, DVM, Iowa State University associate professor and former USDA deputy undersecretary of food safety, has spoken out against the CBS Evening News reports this week regarding antibiotic use in livestock. In his latest comments, Hurd addresses Wednesday night’s airing of CBS’ news segment regarding livestock antibiotic use in Denmark.
Hurd is currently director of the World Health Organization's Collaborating Center for Risk Assessment and Hazard Identification in Foods of Animal Origin at the College of Veterinary Medicine, Iowa State University. He offers the following comments to expand the knowledge of antibiotic use in livestock and balance the CBS News report. (See Hurd's comments on the Tuesday segment of CBS report.)
CBS: Antibiotics in Denmark are used sparingly and only when animals are sick.
HURD: That is true. So sparingly in fact, that farmers and veterinarians are not even allowed to use antibiotics to prevent common illnesses they know are coming. They must wait until pigs suffer and die. According to the World Health Organization, the Danish Pilot Program resulted in an increase in diarrhea in pigs and a 25 percent increase in deaths. In fact, many small farmers were driven out of business due to this ban. The number of farms went from 25,000 in 1995 to less than 10,000 in 2005. What appeared to be a ban on antibiotic use in healthy pigs actually pointed out the benefits of its use in helping pigs grow healthy.
Ironically, once a pig does become visibly sick, the government allows farmers to use antibiotics that are similar to those used in humans. In fact, uses of these antibiotics have risen dramatically since the ban. One of these, tetracycline, is what American teenagers with acne often take for up to six months to treat their condition.
CBS: The experiment to stop widespread use of antibiotics was launched 12 years ago, when European studies showed a link between animals that were consuming antibiotic feed every day and people developing antibiotic-resistant infections from handling or eating that meat.
HURD: No studies ever showed such a linkage. The government records clearly show it was a precautionary action due to the possibility of risk. It should be noted that Denmark is a very small country (about one-third the size of Iowa), which produces fewer pigs than the state of Iowa. So clearly, their “experiment” was not on a national scale in terms of size.
Interestingly, farmers in Denmark are using zinc to prevent post-weaning diarrhea, which again was documented by the WHO. Recent data published by Danish scientists show that the use of zinc may actually be selecting for methicillin resistant staph aureus, which would be another unintended consequence of the ban on antimicrobial growth promoters.
CBS: Since the ban, the Danish pork industry has grown by 43 percent – making it one of the top exporters of pork in the world. All of Europe followed suit in 2006. But the American pork industry doesn't want to.
HURD: In 1997, the Danish pork production was 21,180,000 head. In 2008, the industry had grown to 27,078,000, but about 5 million pigs were exported to other European countries to be fed for market. That means that net growth in the industry was approximately 5 percent, not the 43 percent reported by CBS.
DANMAP 2008 – the Danish government’s own report – states that since 1998, the first year of the ban, active kilograms of antimicrobials used to treat animals increased 110 percent while animal production has only increased 5 percent.
Because Denmark exports more than 85 percent of the pork it produces, it may be important for the government and producers to position the ban as a success, regardless of the apparent negative consequences.
CBS: Without growth-promoting antibiotics, it only costs $5 more for every 100 pounds of pork brought to market in this country.
HURD: According to a recent analysis by Iowa State University, a U.S. ban would increase costs by approximately $6 per animal in the first year. The total cost of a ban to all U.S. pork producers, spread across a ten-year period, could be in excess of $1.1 billion and lead to a 2 percent hike in consumer pork prices.
Even though the ban raised pork prices and put small producers out of business, cost is not really the issue. The focus should be on public health. Did the ban in Denmark improve public health? Neither the World Health Organization nor I find any evidence that it did.
CBS: Dr. Ellen Silbergeld said, "I think the Danish and European experience indicate that there will be real and measurable public health benefits," she said. "There'll be improvements in food safety and actually in the prevalence of drug resistant infections in people."
HURD: The World Health Organization has stated there was no evidence of improved public health (WHO, 2002, pp. 27-29). In fact, resistant rates in human Salmonella cases have increased, and Denmark is currently experiencing their largest outbreak of MRSA in its history. Denmark has seen a largest increase in human MRSA cases since it banned antibiotic growth promotion in animal agriculture.
CBS: According to one study, when different countries introduced certain antibiotics on farms, a surge occurred in people contracting antibiotic resistant intestinal infections one to two years later. One infection, Campylobacter, increased 20 percent in Denmark and 70 percent in Spain.
HURD: The example of resistant Campylobacter does not relate to the use of antibiotics for growth promotion or even of any antibiotics in feed. The type of antibiotic, fluoroquinolones, was used to treat sick animals, and in the United States required a veterinary prescription. In pigs, they were delivered by giving the animals a shot.
The antibiotics that have been used in feed in the U.S. are old— most have been used for more than 40 years. In addition, risk assessments have shown that they do not pose a risk to human health. In fact, FDA surveillance shows that resistance to these antibiotics in pork products is steady to declining.
CBS: After the ban, a Danish study confirmed that removing antibiotics from farms drastically reduced antibiotic-resistant bacteria in animals and food.
HURD: The only resistance that decreased was in Entercoccus spp., which is not a food-borne pathogen (DANMAP 2008).
The total tonnage of antibiotic used in Denmark decreased after the ban. However, please note that the amount of product used to TREAT SICK pigs increased 100 percent. It doubled. Why? Because the prior usage, that was labeled “growth promotion,” was actually preventing illness. It was doing some good. Therefore, it cannot be termed “non-therapeutic.”
Now, the key point is that the type of drug used to TREAT sick pigs was different than what had been preventing disease. These treatment drugs are very similar to those used to treat human illness. So, just what did the World Health Organization say about these events and data?
“It is probable, however, that termination of antimicrobial growth promoters had an indirect effect on resistance to tetracycline resistance among Salmonella Typhimurium because of an increase in therapeutic tetracycline use in food animals.”
“Increased tetracycline resistance among Salmonella may result in additional human Salmonella infections… since persons who take tetracycline for other reasons are at increased risk of becoming infected with tetracycline-resistant Salmonella.”
So, based on this, there might be MORE risk now than before the ban because of an increase in treatments. Also, resistance in human food-borne pathogens, such as Salmonella and Campylobacter has not decreased at all.
CBS: Danish scientists believe if the U.S. doesn't stop pumping its farm animals with antibiotics, drug-resistant diseases in people will only spread. "It's not going to be a time bomb that goes off like this," said Dr. Frank Aarestrup, of the Danish Food Institute at the University of Denmark. "It's something that's slowly getting more and more complicated, more difficult for us to actually treat infections.”
HURD: That’s simply not an accurate description of what America’s pork producers do at all. This is evidenced by the grassroots initiative of Pork Quality Assurance Plus. The program helps guide farmers through the proper and judicious way to handle and use antibiotics responsibly. It’s a program that’s been in place for more than 20 years.
Also, as one of the primary government officials responsible for promoting the idea of a ban on antibiotic growth promoters, Dr. Aarestrup’s professional credibility depends on positioning the ban as a success.
Drug resistance in food-borne disease is not the major concern with human-resistance issues. Less than 1 percent of food-borne illnesses require antibiotic therapy. The human-health crisis with resistance is focused on pathogens that are often hospital-acquired. Thus, bans, such as what Denmark implemented, will not address those issues.
CBS: It costs very little to convert a farm to antibiotic-free. And it doesn't cost consumers much more either. The example was given showing that antibiotic-free pork production would only cost farmers $5 more per hundredweight or 5 cents per pound, so why not just do it to improve human health?
HURD: U.S. economists have shown that if those same antibiotic bans occurred in California, it would add $5 to the cost of every pig. Because I spent three months working in Denmark, I can assure you these effects are real and still present. For this reason, I hope U.S. decision makers will balance this information with the goal of “protecting finite resources while feeding a growing population.”
Antibiotics that prevent animal illness are good for us all. A recent study by Dr. Randy Singer at the University of Minnesota has shown that the consumption of subclinically ill poultry could increase the total number of human illness days.
Any attempt to ban antibiotic use in livestock won’t improve human health, and indeed may result in an increase of food-borne disease. One published risk assessment (Cox, et al.) concluded that there would be 4,500 more cases of food-borne illness if one antibiotic were banned for each one person that may have an extended illness due to use of that antibiotic.