- Bt-maize (corn) during pollination, may trigger disease
in people living near the cornfield.
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- Virtually an entire village of thirty-nine people living
adjacent to a large field of Bt-maize (Dekalb 818 YG) on the island of
Mindanao in the Philippines were stricken by a disease with respiratory,
intestinal, and skin reactions, and fever. The symptoms occurred during
the period when the maize was producing airborne pollen. The residents,
some of whom lived only a few meters from the plants, certainly inhaled
the pollen. The maize was genetically engineered to produce the insecticide
called Bacillus thuringiensis (Bt). In response to Bt-toxin, IgA, IgG,
and IgM antibodies were detected in their blood samples, indicating an
immune reaction to GM maize pollen.
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- Local authorities had proposed that the disease was infectious,
but could not identify the cause. The symptoms of four families, however,
subsided after they left the area to stay with friends or relatives. Upon
returning, the members of all four families once again exhibited the symptoms.
Such a response contradicts the claim that the disease was infectious,
and points to environmental causes.
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- The Norwegian Institute for Gene Ecology learned about
the incident during the fall of 2003 and arranged for blood samples to
be taken in October. The IgA and IgM reactions in their serum indicate
a recent exposure to Bt within the previous three months and are consistent
with an interpretation that the disease might have been created by inhalation
of the Bt -pollen from the field.
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- The maize variety Dekalb 818 was popular in the area.
According to members of the village, seed representatives offered them
an improved version of Dekalb 818, called Dekalb 818 YG. This is a hybrid
between Mon 810, a Bt -crop from Monsanto, and the conventional Dekalb
818 variety. This past year was the first time that Bt maize was planted
in the region. Some villagers said they were never told it was a genetically
engineered variety, and did not know that it was creating its own pesticide.
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- An additional finding from the study showed that the
level of expression of the Bt -toxin Cry1AB varied considerably in the
corn kernels, even from the same plant. The levels ranged from 0.014 ug
to 0.9 ug, with other kernels expressing levels both above and below the
limits of detection of the study.
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- Implications for human health
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- There has been great concern that genetically engineered
crops might increase allergies or immune sensitivity in the population.
Soon after Monsanto's genetically engineered soy was imported into the
UK, for example, soy allergies skyrocketed by 50 percent. (No follow-up
studies were conducted to confirm a link.) At a Russian press conference
held on 11 December 2003, a group of scientists announced that the number
of people with symptoms of allergy increased by three times over the past
three years, and that the increased consumption of genetically engineered
foods by the population might be the cause. Allergies are similarly on
the rise in the U.S., where genetically engineered foods are eaten regularly.
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- Many scientists are concerned that crops genetically
engineered to create the Bt-toxin may, in particular, have adverse immune
and allergenic effects on humans.
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- A U.S. government-funded study published in 1999 confirmed
that farm workers exposed to Bt insecticide sprays exhibited skin sensitization
and the presence of IgE and IgG antibodies, both considered part of an
allergic response. The workers with a greater reaction were those with
more exposure to the spray - another allergy signal.
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- While the workers did not exhibit respiratory symptoms,
the period of exposure was relatively short, and the amount of Bt that
they were exposed to from the spray was quite small. Bt-crops, on the other
hand, create 10 to 100 times the amount of exposure. And the seeds of some
of those Bt -crops have yet another 10 to 100 times that amount.
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- Three mouse studies were conducted on a Bt-toxin, Cry1Ac,
similar to that found in GM cotton and maize varieties. Two of these mouse
studies showed that the Bt -toxin triggers an antibody response in the
blood and mucous membranes of mice; the third demonstrated that Cry1Ac
boosts the immune response to other antigens as powerfully as cholera toxin.
This study verified that Bt also acts as an adjuvant. An adjuvant is an
enabling agent, which increases a person's susceptibility to other allergens
and immunogens. In other words, allergic reactions as a whole might theoretically
increase in a population that is exposed to an adjuvant. This might explain
the increased rate of allergies described above.
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- In a study published in Natural Toxins, mice were fed
a diet spiked a natural Bt -protein. When the researchers analyzed tissue
sections from the ileum (the lower part of the small intestine) by electron
microscopy, they found significant structural disturbances and intestinal
growth.
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- All of these animal studies conclude that Bt is active
in mammals, doesn't degrade, may bind to the intestines, and therefore
may pose a threat to human health. These studies suggest that feeding the
Bt-crops to humans and animals may be premature.
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- Bt-corn would not pass the FAO/WHO recommended tests
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- In spite of the evidence that Bt creates reactions in
mice, regulatory authorities such as the U.S. Environmental Protection
Agency (EPA) have stated that Bt-toxin is not supposed to survive long
enough to even get into the small intestine. It's supposed to be degraded
in the stomach. They base their claim on test tube experiments conducted
by the biotech companies. The Bt -protein is put into a test tube containing
simulated gastric fluid - a mixture of hydrochloric acid and pepsin, a
digestive enzyme - which, they claim, mimics the act of digestion in the
stomach. The longer the protein stays intact, the greater the opportunity
for it to elicit the antibody response associated with allergy.
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- The FAO/WHO likewise propose a test-tube evaluation of
protein stability. Although Monsanto's test on its own Bt-maize protein
(Cry1Ab) resulted in over 90 percent degradation after just two minutes,
critics point out that the strength of the acid and the relative amounts
of enzyme and Cry1Ab Monsanto used in their test tube was unrealistic and
specifically designed to destroy the protein as quickly as possible. Monsanto
used a pH of 1.2, as compared to the considerably milder 2.0 recommended
by the FAO/WHO. Also the ratio of pepsin to Cry1Ab used was about 1,250
times greater than the FAO/WHO standard. When that same Cry1Ab was independently
tested using a different solution, 10 percent of Monsanto's Bt-toxin protein
lasted one to two hours, not two minutes. If the researchers had used the
FAO/WHO guidelines, however, more of the protein would have lasted even
longer. Furthermore, another test tube study showed that Cry1Ab only breaks
down to sizeable fragments - large enough to remain potentially allergenic
and larger than the maximum size specified by the FAO/WHO. (In any case,
many scientists have pointed out that the test-tube studies as a whole
are flawed, as they do not approximate actual conditions, and survival
of Bt -protein has already been confirmed in animal models.)
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- A second method for investigating allergenicity recommended
by the FAO/WHO and others involves comparing the structure of the foreign
protein to those of known allergens. The reasoning is that if a section
of the GM protein's amino acid sequence is similar or identical to that
of a known allergen, it might trigger a reaction. A researcher at the U.S.
Food and Drug Administration (FDA) discovered such a similarity between
Cry1Ab and an egg yolk allergen.
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- Genetic instability makes allergy testing even more problematic
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- The finding that corn kernels express different levels
of the Bt -toxin make existing allergy safeguards much more problematic.
The level of protein that is tested by scientists may not represent the
actual level the public is exposed to.
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- http://www.seedsofdeception.com/utility/showArticle/?objectID=36
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