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Biotech / Medical : Monsanto Co. -- Ignore unavailable to you. Want to Upgrade?

To: Anthony Wong who wrote (2100)	5/29/1999 8:17:00 PM
From: Dan Spillane	Respond to of 2539

This is pretty shocking; they said this stuff was "safe" for organic gardens... From New Scientist, 29 May 1999 Red flag for green spray Debora Mackenzie BACTERIAL SPORES sprayed on organic crops as a pesticide may damage the health of people who inadvertently breathe them in. French researchers have found that inhaling the spores can cause lung inflammation, internal bleeding and death in laboratory mice. Bacillus thuringiensis, or Bt, produces a toxin that kills insects. The dried spores of the bacteria have been used as a pesticide for more than 30 years and are one of the very few insecticides sanctioned for use on organic crops in Europe. Bt is also widely used to combat pest such as the spruce budworm, a caterpillar that attacks trees. Last year, French scientists isolated a strain of Bt that destroyed tissue in the wounds of a French soldier in Bosnia. The strain, known as H34, also infected wounds in immunosuppressed mice (This Week, 30 May 1998, p 7). Now the same team has found that H34 can kill mice with intact immune systems if they inhale the spores. Françoise Ramisse of le Bouchet army research laboratories near Paris and her colleagues found that healthy mice inhaling 108 spores of Bt H34 died within eight hours from internal bleeding and tissue damage. Spores from mutants of the same strain which did not produce the insecticide were equally lethal to mice, suggesting that it was not to blame. Ramisse and her colleagues presented their results at a conference in Paris last month. The researchers think that the symptoms are caused by other toxins. The bacterium's close cousin, Bacillus cereus, produces a toxin that ruptures cell membranes. And in 1991, Japanese researchers showed that B. thuringiensis produces the same toxin. In fact, when the French researchers ran samples from the soldier from Bosnia through an automated medical analyser, it seemed to show that the bacterium was B. cereus. Ramisse suggest that companies producing Bt spores might make them safer by deleting the promoter sequence that activates the gene for the membrane-rupturing toxin. Although H34 is not used as a pesticide, commercial strains of Bt tested by the researchers also killed some mice or caused lung inflammation when inhaled. The team obtained these strains from Abbott Laboratories, a major supplier of Bt based in Chicago. Ramisse points out that the strains are sprayed on forest pests at concentrations of 1011 spores per square metre--and so might pose a danger to people in the immediate vicinity. But Abbott maintains that Bt is safe. "We stand by our products," says Linda Gretton, a company spokeswoman. The French researchers have not yet tested strains made by other companies. "I suspect Bt infection is more widespread than we realise," says Ramisse. Recorded infections by Bacillus pathogens are comparatively rare. Known pathogenic species can have very distinctive symptoms. Anthrax, for instance, is caused by B. anthracis. But where such tell-tale signs are absent, Ramisse suspects that doctors often fail to recognise that the bacteria are responsible, dismissing any Bacillus in patients' cultures as contamination. Consequently, the cultures are often discarded. "I wish they would start keeping them so we could check for Bt," she says. When Bt was sprayed in towns in Oregon in 1991 to combat gypsy moths, the bacterium was found in clinical samples from 55 patients who had been admitted to hospital for a variety of other reasons. Robert Haward of the Soil Association, which represents Britain's organic farmers, says that they may have to use masks and take more care when spraying the spores on crops. newscientist.com

To: Anthony Wong who wrote (2100)	5/31/1999 1:38:00 PM
From: Dan Spillane	Read Replies (1) \| Respond to of 2539

Call for ban on BT spray? Note, from the story I posted earlier, "commercial strains of Bt (spray)tested by the researchers also killed some mice or caused lung inflammation when inhaled." Obviously, such BT spray will kill caterpillars (Monarchs, et. al) quite effectively, more so than the BT corn pollen. However, now we know the BT spores from spraying can infect and kill mice, according to the study. This also means BT spray will kill creatures in or near the field, such as birds or rabbits. And what about spray drift to humans? The H34 strain is lethal, and we can never be sure when that strain might show up in BT spray...BT spray could even cause a plague. Importantly, it is the BT BACTERIA that cause these additional problems, NOT the BT toxin itself. Therefore, in the case of BT crops (such as the corn), there is no such problem. This is because the BT crops contain only the gene which produces the BT toxin to kill the insects, which has been proven to be safe. On the other hand, the BT spray contains ENTIRE LIVE bacteria, which can infect animals and people, possibly even resulting in death. What this all means is that we should not be deploying BT via bacteria, since it can have unpredictable and deadly consequences, and affects a wider number of creatures than previously thought, including humans. The controversial BT corn is much safer in this respect; the other crops such as cotton and potatoes (which don't carry the BT pollen risk to butterflies) are perhaps the best uses of BT yet made. I noticed Greenpeace called for a ban on BT corn in Europe, based on the butterfly experiment. When will Greenpeace call for a ban on BT spray due to the new evidence that it can infect and kill animals and humans? The public deserves to be protected on this count, infectious spray is way more dangerous than BT corn pollen, since many more creatures (and humans) could be killed or injured. Dan