Kiera Butler

Kiera Butler

Senior Editor

A senior editor at Mother Jones, Kiera covers health, food, and the environment. She is the author of the new book Raise: What 4-H Teaches 7 Million Kids—and How Its Lessons Could Change Food and Farming Forever (University of California Press).

 

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Antibiotics Are No Longer Making Pigs Bigger

A new study casts doubt on the standard practice of dosing animal with drugs to increase their size.

| Tue Mar. 10, 2015 3:17 PM EDT

For decades, it's been thought that low, regular doses of antibiotics help livestock grow big—thus increasing meat producers' profits. So common is the practice of lacing farm animals' feed with the drugs that an astonishing four-fifths of all antibiotics in the United States now go to livestock.

But a new meta-analysis by two Princeton researchers shows that antibiotics aren't as effective at promoting growth as they used to be. Studies from 1950-1985 suggested that antibiotics increased weight of young pigs by an average of about 17 older pigs by 4 percent. But similar studies since 2000 found much less dramatic results: 1 percent increase for young pigs and no measurable increase for older pigs.

No one knows why the drugs have become less effective—and in fact, there's no consensus on how exactly antibiotics increased growth in animals to begin with. One theory is that the drugs fight low-level infections, which allows the animal to use its energy for growing instead of warding off germs. The authors of the new analysis theorize that as hygiene at livestock operations improve, the rate of infections might be decreasing, thus negating the need for antibiotics.

Another (scarier) possibility: Bugs that cause common animal infections are becoming resistant to the antibiotics. The consequences of antibiotic resistance, of course, go far beyond pigs' rates of growth. As my colleague Tom Philpott has reported, superbugs can jump from animals to humans. Antibiotic-resistant infections already kill 700,000 people every year worldwide. A recent UK report predicted that number will rise to 10 million by 2050.

"If the benefits of [antibiotics for animal growth] have diminished, then it becomes reasonable to be cautious and avoid the potential public health costs," write the new report's authors. "Antibiotics are not needed to promote growth, but they are essential to treat infectious diseases and maintain animal health." 

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McDonald's Just Banned Antibiotic-Laced Chicken. Here's Why That Matters.

Antibiotic resistance is real—and meat production is helping to spread it.

| Thu Mar. 5, 2015 7:49 PM EST

This week, McDonald's pledged to phase out serving chicken raised on antibiotics that can also be used to treat humans. To understand the giant implications this has for the meat industry, consider my colleague Tom Philpott's previous reporting on the topic. For starters, the livestock industry uses an astounding four-fifths of all antibiotics consumed in the United States. Mostly, these drugs are used not to treat infections but to promote growth in animals.

There is evidence that livestock antibiotic use contributes to antibiotic resistance, lessening the effectiveness of drugs that are medically important to  humans. And scientists have observed so-called "superbugs" migrating from farms to outside communities. It's a major problem—indeed, scientists predict that antibiotic failure will kill 20 million people by 2050. And yet, despite all this, the government still allows livestock producers to dose their animals with antibiotics.

McDonald's chicken move is a tacit acknowledgement that antibiotics are a precious resource. And considering that the chain serves 68 million people a day in practically every nation on Earth, it sends a powerful message indeed.

6 Terrifying Facts About Measles

For starters: It's one of the most contagious diseases known to man.

| Wed Jan. 28, 2015 7:00 AM EST

The current outbreak of measles that began in California has sickened 86 people and landed 30 babies in home isolation. The California Department of Health has issued an official warning that "any place where large numbers of people congregate and there are a number of international visitors, like airports, shopping malls and tourist attractions, you may be more likely to find measles, which should be considered if you are not vaccinated."

Not everyone is so concerned. In a Facebook post on January 16, celebrity pediatrician Robert "Dr. Bob" Sears encouraged his followers not to "let anyone tell you you should live in fear of" measles. "Ask any Grandma or Grandpa (well, older ones anyway)," he wrote, "and they'll say 'Measles? So what? We all had it. It's like Chicken pox.'"

Well, Dr. Bob is wrong—measles is serious business. Consider these facts:

  1. Measles is one of the most contagious illnesses known to man. According to the Centers for Disease Control and Prevention (CDC), it infects about 90 percent of people who come into contact with it. The virus can survive on surfaces or even in the air for up to two hours. That means that if an unvaccinated person happens to pass through a room where someone with measles was a few hours before, he or she has a very high chance of contracting the disease. 
     
  2. Some people who get measles become seriously ill. Before the advent of the measles, mumps, and rubella (MMR) vaccine, between 3 and 4 million people contracted measles each year in the United States. Of those, 48,000 were hospitalized, 4,000 developed the life-threatening brain condition encephalitis, and 400 to 500 died.
     
  3. Almost everyone needs to be vaccinated for measles in order to protect the most vulnerable people. The epidemiological concept of "herd immunity" means that enough people in a given community are immunized so that people who can't get vaccinated—infants that are too young to receive vaccines, people who can't get vaccinated because their immune systems are not strong enough, and the small number of people for whom the vaccine doesn't work—are protected. The threshold for herd immunity varies by disease; for measles, it's 92 to 94 percent.
     
  4. In some places in the United States, MMR vaccination rates among kindergartners aren't anywhere near the herd immunity threshold. In Marin County, California, only 80 percent of students are up to date on their vaccinations. In Nevada County, California, the figure is 73 percent. New York magazine reported last year that dozens of New York City private schools had immunization rates below 70 percent. (Californians can check rates at individual schools here.)
     
  5. Worldwide, measles is far from eradicated. According to the CDC, in 2013, more than 60 percent of children in the Democratic Republic of the Congo, Ethiopia, India, Indonesia Nigeria, and Pakistan were not adequately vaccinated against measles. Seventy percent of measles deaths worldwide occurred in those countries.
     
  6. Measles could make a major comeback in the United States. It's happened in other developed nations: In the mid-1990s, UK public health officials considered measles eradicated in the country—but in 2008, because of low vaccination rates, measles once again hit endemic status. Between 2008 and 2011, France saw more than 20,000 cases of measles—after virtual elimination of the disease just a few years before.
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