Thursday, October 10, 2002

Aflatoxin, Again

So the Aflatoxin debate goes on. I received a particularly cogent counterpoint to yesterday's post, debunking the effectiveness of Aflatoxin as a weapon, from Lynxx Pherrett:
Take what you read in Salon (even when reprinted on PUK) with a grain of salt, or a truckload, depending.

You probably heard about aflatoxin because it is a common mold toxin on grains and nuts.
In Florida, Georgia, and Alabama—top peanut-producing states—aflatoxin outbreaks from 1993 to 1996 caused losses averaging $26 million annually, ARS economist Marshall C. Lamb estimates.

The most potent strain is B1. It's also pretty useless as a weapon.
The classic example of the perceived short-term and long-term negligible effect on humans is this chronology of a suicide attempt using aflatoxin the Food and Drug Administration described as follows:

[A] laboratory worker ingested 12 m g/kg body weight of aflatoxin B1 per day over a 2-day period and 6 months later, 11 m g/kg body weight per day over a 14 day period. Except for transient rash, nausea, and headache, there were no ill effects; hence, these levels may serve as possible no-effect levels for aflatoxin B1 in humans. In a 14-year follow-up, a physical examination and blood chemistry, including tests for liver function, were normal.

Wannemacher and others estimate the lethal aflatoxin B1 dose for 50% of the exposed population is one to four milligrams per kilogram of human body weight. In practical terms, a 175-pound person would have to breathe in or eat an acute dose of between 80 to 318 milligrams of pure aflatoxin B1 to cause death. Compared with botulinum toxin, this dose is approximately one million times larger. Such a dose would be very difficult if not impossible to introduce into a human through inhaling a dry or wet aerosol.

And if you're worried about the effects of micro-dosages over the long term, you might just have to give up eating. The USDA limit for aflatoxin on peanuts, for example, is 15ppb -- so you've been eating peanut products at 14ppb or so your entire life.

Back to the osd report
The London Hospital’s study on the effects of aflatoxin-contaminated feed established a dose/effect relationship between aflatoxin and liver cancer in rats. Feeding contaminated nut meal to rats produced liver cancer. For example, with pure aflatoxin B1, all the rats developed cancer by week 88 at a dose of 100 micrograms per kilogram of body weight. However, cancer failed to develop almost completely when using adult mice and hamsters as subjects. In rats, aflatoxin B1 is the deadliest cancer-causing compound. However, adult mice are essentially totally resistant to aflatoxin’s cancer-causing properties because of how different species’ livers process aflatoxin. Casarett and Doull’s Toxicology, a standard textbook, states though aflatoxins have been studied and cause liver cancer in laboratory rats, the link to human liver cancer has not been proved. The wide range of susceptibility to aflatoxin B1 makes extrapolating animal data to humans difficult.

Causes liver cancer in rats--not adult mice--not adult hamsters--and how much it would take over how long to cause liver cancer in humans (children or adults), or even if it does at all, is unknown.

Why'd Saddam bother producing it. The speculation in the osd report is that it might have been because aflatoxin "is easier to manufacture than most other toxins, the Iraqi biological warfare program’s staff might have chosen to produce it to meet production goals set by higher authorities rather than its perceived biological warfare value."

Since we know that all children in the US have been exposed to corn, wheat, soybeans, rice and probably peanuts we also know that all have been exposed to some minute levels of aflatoxin--of course, since we were children, we ate the same foods, and at higher exposure rates before USDA testing, and we haven't all died of liver cancer yet.

USDA info -
The FDA will consider action if aflatoxin levels exceed:

20 ppb - For corn and other grains intended for immature animals (including immature poultry) and for dairy animals, or when its destination is not known;

20 ppb - For animal feeds, other than corn or cottonseed meal;

100 ppb - For corn and other grains intended for breeding beef cattle, breeding swine, or mature poultry;

200 ppb - For corn and other grains intended for finishing swine of 100 pounds or greater;

300 ppb - For corn and other grains intended for finishing (i.e., feedlot) beef cattle and for cottonseed meal intended for beef cattle, swine or poultry

So, maybe "[a]flatoxin is so insidiously dangerous" it's reason all by itself to eliminate Hussein (though there's plenty of other, probably better reasons), or maybe Saddam's aflatoxin is about as dangerous as "weaponized" Jello: they have to hold the victim's face in the bowl until they suffocate, but hey, it's weaponized.
Whew!! Sort of makes you pause before you believe what you read. What he says could be applied to most if not all bio-weapons. While Smallpox, Abthrax, and other biological agents have not been well tested in combat, when they have been, their effects have been of questionable effect. That's why I doubt the accuracy of the term "weapons of mass destruction." Biological weapons, in actual use, don't seem to cause very militarily significant effects. They are better used against civilian targets.

But, whatever the actual effects of Aflatoxin, the idea behind weaponizing this stuff is to slowly poison civilian populations, whether it works well or not. Its development points to a particularly virulent mental state on the part of Saddam Hussein. We can only hope that the phurry Pherrett's research reveals only one in a series of mistakes that the Butcher of Baghdad has made. Meanwhile, Lynxx, would you eat a teaspoonful of Aflatoxin in your cornflakes, just to prove to us that it is really so harmless?