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BTK Fact Sheet Questions and Answers about Gypsy Moth Spraying and Your Health What is Btk? What is Foray® 48B? Are there any risks associated with the Gypsy Moth? Can Btk make people sick? Is there any information about Btk and people's health in Oregon? What about people with weakened immune systems and people with allergies? What should I do during the spraying? What if I have more questions? What is Btk? Bacillus thuringiensis (Bt) is a bacterium commonly found in nature as a normal resident of soil. It occurs in many forms, several of which are used as biological pest control agents on food crops-including organically grown foods. Bacillus thuringiensis var. kurstaki or Btk, makes a crystal which affects the Gypsy Moth larva or caterpillar. In order to work, the bacterium must be eaten by the Gypsy Moth caterpillar. Conditions needed for the Btk to be activated are found only in the stomach of moth and butterfly caterpillars. These conditions are not found in animals, birds and other desirable insects such as bees, beetles, and spiders. Nor are these conditions found in people. What is Foray® 48B? Foray® 48B is a water-based product containing 17.19% Btk. At the manufacturing plant, samples of the material are checked to make sure no harmful bacteria or toxins are present in the formulation. In addition to the bacterial ingredient, Foray® 48B contains a number of “inert” ingredients, including stickers and binders that help the spray remain on vegetation after it is applied. No petroleum products are used as carriers. Foray® 48B contains water, carbohydrates, proteins from grain sources like corn or soybeans, Btk spores and crystalline proteins, stabilizers for acid control, several preservatives and wetting agents. The EPA categorizes inert ingredients, which might be used in pesticides. Please refer to the EPA website for more information, http://www.epa.gov/opprd001/inerts/ Are there any health risks associated with the Gypsy Moth? Gypsy moths are mainly a threat to trees and shrubs. When the number of the caterpillars has been very high, some people have had allergic reactions. The Gypsy Moth caterpillars have spiny hairs which can cause welts or a rash, lasting up to 4-5 days. Population levels of Gypsy moth in isolated infestations such as those we have in Oregon, do not normally pose any health risks. Can Btk make people sick? Btk has an excellent safety record for humans. If you eat vegetables, you probably have already ingested this bacterium. It is commonly used on commercial, and even organic, produce. The safety has been established both by laboratory research and monitoring people in the areas of the U.S., Canada and New Zealand where it has been used for more than 25 years. Evidence to support this includes:
Laboratory animals exposed to Btk by feeding, breathing, injection through the skin, and application into abrasions were not harmed by the exposures.
People without a direct exposure to the material are unlikely to have any symptoms. However, some people working directly with Btk spray for long periods of time have had mild skin irritation or short term breathing problems. After a thorough review of the toxicity of Btk products, including both active and inert ingredients, the U.S. EPA, Health Canada, the World Health Organization, and many other groups have found it safe and effective for aerial applications when used according to label directions. Is there any information about Btk and people's health in Oregon? This product has been applied on many occasions in the United States, Canada, New Zealand and elsewhere over the last 25 years. It has been applied previously by aircraft in Oregon many times. The Health Division and county health departments conducted public health tracking of illnesses possibly related to Gypsy Moth spraying during previous spray programs in Lane County in 1985-6 and the Portland Metropolitan area in 1987 and 1992. The tracking included reports from doctors and information on hospital emergency room visits. There was no increase in illnesses among people living in spray areas that could be linked to the spraying. In 1986, the Health Division conducted a special study of health complaints related to the spraying. No unusual patterns of illness complaints were identified. Cultures (blood, urine, throat, wound, etc.) from patients in the spray area were evaluated to determine if Btk was present. When Btk was found in the culture from a patient, that person's medical record was reviewed to determine whether the Btk had caused illness. We found 58 patients with cultures that grew Btk. In 55 of these instances, it was determined that Btk was probably a contaminant of the culture, not the cause of illness. In three patients, there was some evidence that the positive cultures resulted from contamination, but it could not be conclusively determined whether Btk was a contaminant of the culture or the cause of illness. All three patients had pre-existing medical problems. In 1992, the Multnomah County Health Department and the Health Division jointly monitored the population in the spray area for signs of ill health effects. A total of 66 calls were received from people living in the spray zone, who reported symptoms which they thought may have been caused by the Btk spray. Most of the symptoms reported were minor and were not clearly associated with the spray when complaints were investigated. No positive cultures for Btk infection were found. What about people with weakened immune systems and people with allergies? Although we don't have evidence that Btk will affect any given group of people, individuals with leukemia, AIDS, or any other physician-diagnosed causes of severe immune disorders, may consider leaving the spray area during the actual spraying. If you or someone in your home has one of these conditions, ask your doctor for advice about avoiding exposure before the spray project begins. The Btk product contains residues of grains and other foods used to help the bacteria grow. If you have serious allergies to foods or food preservatives, your health care provider may consult with the manufacturer of Foray® 48B (Valent Biosciences – 1-800 323 9597). What should I do during the spraying? Even though the spray is considered safe for humans, we recommend that people stay indoors during spraying, unless it is essential to be outdoors. You should be advised in advance by the Department of Agriculture when spraying will occur, so you may plan accordingly. This is general advice for the public. If you or someone in your home has a medical problem that they believe may be made worse by the spraying, talk to your health care provider. If your drinking water source is from open surface water (e.g., creeks, streams, springs) and you are concerned about potential exposure, you may wish to shut off the intake during the spray and until you are satisfied that any water exposed to the spray has moved downstream of your intake. Alternative water sources in the interim might include previously stored and covered water on site, bottled water, or water from a neighbor outside the sprayed area. To avoid exposure, we recommend:
What if I have more questions? If you want more information about Btk, call the National Pesticide Information Center (NPIC), based at Oregon State University, at 800-858-7378 or visit their website at http://npic.orst.edu [A Btk Fact Sheet is at http://npic.orst.edu/factsheets/BTgen.pdf ] If you have been exposed to Btk and you have concerns about possible health effects, wash the affected area and contact the Oregon Poison Center at 1-800-222-1222. If you have serious allergies to food or food preservatives, your health care provider may consult with Oregon Health Services at 971-673-0977 or the manufacturer, Valent Biosciences, 1-800 323-9597. For further information on Btk, call the Oregon Department of Agriculture at 503-986-4635. |
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