Running from the green monster

By Marc Siegel

SPINACH IS disappearing from supermarket shelves with the news that E. coli is hiding in the country's bagged spinach. Many of us fear our next bite. But while it is true that only small amounts of this deadly bacteria, known as 0157:H7, are sufficient to infect us, there is no evidence that the problem is pervasive.

The Food and Drug Administration is right to be ultra careful in issuing its warnings even if it prevents only a single death in the process. The Natural Selection Foods processing plant where the problem seems to have originated has no choice but to remove its products from the shelves. But as the Centers for Disease Control and Prevention joins the FDA in tracking and reporting on the problem, it is too easy for the public to assume that the problem is reaching monstrous proportions. It is not. We must keep in mind that there has been only one death, 14 cases of kidney failure, and just over 100 people have become ill from ingesting the tainted spinach. Our infectious fears spread faster than any bacteria and ignite a sense of imminence that far eclipses the reality.
Still, there is a problem worthy of public health attention. Government agencies are not integrated enough when it comes to food. The USDA is in charge of animals and plants, and the FDA monitors food, but an outbreak like this can fall in a gap between them. Organic fertilizers are not well regulated, and can too easily contaminate vegetables or ground water.

E. Coli is a common bacteria; trillions of strains that don't make us ill thrive and multiply in our intestines. But the 0157:H7 strain, which has been found in cow intestines, makes a toxin that damages human blood vessels and can cause blood clots and damage kidneys, especially in children. Cows don't have the receptors in their blood vessels to pick up the toxin, so they are asymptomatic carriers.

A 2002 US Department of Agriculture study found that 38.5 percent of dairy farms had a cow that tested positive for 0157:H7, with just over 4 percent shedding the bug in their manure. The shedding is intermittent, so it takes an effective and thorough screening program to discover this E. coli before it spreads. Crops are at risk, especially in farms that rely on manure for fertilizer.

There have been 11 reported outbreaks of this E. Coli in salad foods since 1995. The latest outbreak is not the largest in terms of size (1,000 people were infected at a state fair in upstate New York in 1999), but it does seem to be the most virulent, with two to three times the rate of kidney failure than expected.

Why is this latest strain so virulent? The answer, in part, appears to be due to the overlapping way we raise our cattle and process our foods and other bovine products. Bacteria can survive and multiply easily in non-sterile environments. The common practice of feeding antibiotics to cows can backfire by leading to an overgrowth of strains that are drug resistant.

What to do about the bacteria? Some studies suggest that feeding cattle hay rather than grain, or injecting them with ``pro-biotic" bacteria may help to reduce the prevalence of 0157:H7. At the national level, we need more integrated food-safety measures, a better way to coordinate the FDA and the USDA animal and food inspections. This could be accomplished by a new food-safety agency that acts as a bridge, or by expanded regulatory roles in both the FDA and the USDA.

In the meantime, we need to inoculate ourselves against our fear of an outbreak that is more of a wake-up call than an extensive risk.

Marc Siegel is an associate professor of medicine at NYU School of Medicine and author of ``False Alarm: The Truth About the Epidemic of Fear," recently released in paperback.

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Copyright © 1990-2007 Marc K. Siegel, M.D.