Exposure to Bt sprays may lead to allergic skin sensitization and induction of IgE and IgG antibodies, or both based on recent scientific studies. Although health risks to pesticides containing Bacillus thuringiensis (Bt) have been minimal, the potential allergenicity of these organisms has not been evaluated. Today large acreage of US crops like soy, corn, canola and others are genetically engineered (GE) to contain Bt in every plant cell and USDA has failed to evaluate the adverse health effects of large-scale Btk [Bt kurstaki, a strain of Bt toxin] spraying on a population where people are likely consuming GE food crops and may be developing skin sensitization and immune reactions to Bt. To date, USDA has egregiously failed to mention the likelihood of skin sensitization and immune reactions to the Btk pesticide spray in GE food consumers.
A health survey was conducted in farm workers before and after exposure to Bt pesticides. The investigation included questionnaires, nasal/mouth lavages, ventilatory function assessment, and skin tests to indigenous aeroallergens and to a variety of Bt spore and vegetative preparations. To authenticate exposure to the organism present in the commercial preparation, isolates from lavage specimens were tested for Bt genes by DNA-DNA hybridization.
Please read more on the adverse health effects of widespread Bt use in food crops in the following excerpt from a 1999 study in the Journal of Environmental Health Perspectives.
Environmental Health Perspectives Volume 107, Number 7, July 1999 Immune Responses in Farm Workers after Exposure to Bacillus Thuringiensis Pesticides http://www.ehponline.org/members/1999/107p575-582bernstein/bernstein-full.html
[details of authors at end]
“In addition to the implication that skin sensitization to Bt in pesticides could be a precursor of clinical IgE-mediated diseases, several aspects of this investigation may be relevant to other current health issues: immediate hypersensitivity induced by bacteria and transgenic foods engineered to incorporate pesticidal genes in their genomes. First, because skin sensitivity to spore and vegetative components of a nonpathogenic species of Bacillus was clearly demonstrated, future awareness about the allergenic potential of environmental bacteria should be increased, even though this phenomenon has been recognized for relatively few such organisms (e.g., Staphylococcus aureus, Streptococcus pneumoniae, and Moraxella catarrhalis) (19,20). There is presently strong evidence of a close molecular genetic relatedness between Bt subspecies and the B. cereus food pathogen that would support this call for caution (21,22).
Further, in the case of the Bacillus genus, the possibility of cross-allergenic epitopes in an unrelated species such as B. subtilis should be appreciated because this organism or its products may occur in both occupational and nonoccupational environments (23,24).
Conversely, results of this investigation should partially allay recent concerns about the occurrence of possible adverse health effects in consumers after exposure to transgenic foods (25,26). Because reactivity to the Btk pro-delta-endotoxin was only encountered in 2 of 123 workers sensitized by the respiratory route, it is unlikely that consumers would develop allergic sensitivity after oral exposure to transgenic foods (e.g., tomatoes, potatoes) that currently contain the gene encoding this protein. However, future clinical assessment of this possibility is now feasible because of the availability of reliable Bt skin and serologic reagents developed during the course of this investigation.”
19. Leung DY, Harbeck R, Bina P, et al. Presence of IgE antibodies to staphylococcal exotoxins on the skin of patients with atopic dermatitis. Evidence for a new group of allergens. J Clin Invest 92(3):1374-1380 (1993). 20. Brarda OA, Vanella LM, Boudet RV. Anti-Staphylococcus aureus, anti-Streptococcus pneumoniae and anti-Moraxella catarrhalis specific IgE in asthmatic children. J Investig Allergol Clin Immunol 6(4):266-269 (1996). 21. Carlson CR, Johansen T, Lecadet M-M, Kolsto A-B. Genomic organization of entomopathogenic bacterium Bacillus thuringiensis subsp. berliner 1715. Microbiology 142:1625-1634 (1996). 22. Damgaard PH, Larsen HD, Hansen BM, Bresciani J, Jorgensen K. Enterotoxin-producing strains of B. thuringiensis isolated from food. Lett Appl Microbiol 23:146-150 (1996). 23. Johnson CL, Bernstein IL, Gallagher JL, Bonventre PF, Brooks SM. Familial hypersensitivity pneumonitis induced by Bacillus subtilis. Am Rev Respir Dis 122:339-348 (1980). 24. Bernstein IL. Enzyme allergy in populations exposed to long-term, low-level concentrations of household laundry products. J Allergy Clin Immunol 49:219-237 (1972). 25. Goodman RM, Hauptli H, Crossway A, Knauf VC. Gene transfer in crop improvement. Science 234:48-54 (1987). 26. Introduction of Recombinant DNA-Engineered Organisms into the
Environment: Key Issues. Washington, DC:National Academy Press, 1987.
USDA has egregiously failed to mention the likelihood of skin sensitization and immune reactions to the Btk pesticide spray in GE food consumers.
It’s highly disconcerting that USDA has grossly failed to inform the public, inside and outside the spray zone, that a number of exposed children, pregnant women, persons with pre-existing illnesses, senior citizens, chemically sensitive persons, and healthy adults may suffer adverse health effects such as skin sensitization and immune reactions from the large number of Bacteria in the Btk pesticide spray.
Will the USDA pay for medical expenses and health care costs if people are injured? No. The USDA will deny health effects just like they have at other locations in Oregon, Washington state and other places.
NEIL J. CARMAN, PH.D.
NEIL J. CARMAN, PH.D.