Subject: Scientists to Call for a Ban on Btk---- Date: Fri, 28 Apr 2000 07:48:42 -0400 From: Stephen Tvedten Organization: Get Set Inc. (www.getipm.com)
To: Lyndon Hawkins Senior Research Scientist State of California, Department of Pesticide Regulation - Integrated Pest Management
Dear Lyndon, I thought you might like to read some more sound science on another of your "registered" insecticides. The article appeared in The Medical Post VOLUME 35, NO. 25, July 6, 1999, and was entitled: Insecticide's ill effects on mice prompt French scientists to call for ban - By Karen Birchard
PARIS - French government scientists have called for a ban on the insecticide Bacillus thuringiensis (Bt) after finding that inhaled spores cause lung inflammation, internal bleeding and death in laboratory mice. Dried Bt spores is one of the few insecticides sanctioned for use on organic crops in Europe. It is also used widely, including in Canada, to combat forest pests such as the spruce budworm. Last year, a team led by FranÁoise Ramisse of le Bouchet army research laboratories near Paris isolated a strain of Bt that had destroyed tissue in the wounds of a French soldier in Bosnia. The strain, known as H34, also infected wounds in immunosuppressed mice. Now the same team has found that H34 can kill mice with intact immune systems if they inhale the spores. According to the May 29 edition of New Scientist, the researchers found that healthy mice inhaling 100 million spores of Bt H34 died within eight hours from internal bleeding and tissue damage. Spores from mutants of the same strain that did not produce the insect-killing toxin were equally lethal to mice, suggesting the toxin was not to blame. The researchers think the symptoms are caused by other toxins. The bacterium's close cousin, Bacillus cereus, produces a toxin that ruptures cell membranes. In 1991, Japanese researchers showed that B. thuringiensis produces the same toxin. In fact, when the French researchers ran samples from the soldier through an automated medical analyser, it seemed to show that the bacterium was B. cereus. Ramisse suggested companies producing Bt spores might make them safer by deleting the promoter sequence that activates the gene for the membrane-rupturing toxin. Although H34 alone 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 (the supplier to the Ballard / Magnolia project), based in Chicago.
Ramisse pointed out that the strains are sprayed on forest pests at concentrations of 100 billion spores per square metre, and therefore might pose a danger to people in the immediate vicinity. But Abbott maintains Bt is safe. "We stand by our products," said Linda Gretton, a company spokeswoman. The French researchers have not yet tested strains made by other companies but they believe Bt infections may be more widespread than suspected. Determining the extent of the problem is difficult because doctors tend to dismiss any Bacillus in patients' cultures as contamination, Ramisse said. Consequently, the cultures are often discarded. "I wish they would start keeping them so we could check for Bt."
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.
Well Lyndon, why do you "register" any toxin without adequate study? Why do we have to suffer and/or die before you decide to "unregister or test" the POISON?