1900 Richmond Ave., Victoria, British Columbia, Canada, V8R 4R7 Tel (250) 519-7066

QUESTIONS AND ANSWERS ABOUT "BTK" AND HEALTH

Introduction

The provincial government plans to carry out a pesticide spray program in the greater Victoria area this spring in order to eradicate the North American Gypsy Moth. Over the period April 1 to June 30, Foray 48B, a bacterial insecticide will be applied to selected areas of Southern Vancouver Island, including parts of the Capital Regional District, Duncan and Nanaimo using aircraft. The application of Foray 48B has been approved by an Order in Council of the Provincial Cabinet at the request of the Ministry of Forests, Ministry of Environment Lands and Parks, and the Ministry of Agriculture and Foods to combat an infestation of the Gypsy Moth. The implications of an infestation with Gypsy Moth, an imported pest species, are believed to be serious enough to warrant eradication. Because of the large areas involved (approx 13,400 ha) and other factors, aerial application of Foray 48B is considered to be an effective means, and the only feasible means, to eradicate this infestation.

What is Foray 48B?

Foray 48B is a water-based product containing a bacterium called Bacillus thuringiensis var.Kurstaki (BtK).

This bacterium is a biological pest control agent found in nature as a normal resident of soil. In order to work, the bacterium must be eaten by the Gypsy Moth caterpillar. The conditions for the BtK to work are found only in the stomach of moths and butterfly caterpillars. These conditions are not found in animals, birds and other desirable insects such as bees, beetles and spiders.

At the manufacturing plant samples of the spray are checked to make sure that no harmful bacteria or toxins are present in the formulation.

In addition to the bacterial ingredient, Foray 48B contains a number of so-called inert ingredients, including stickers and binders that help the spray remain on vegetation after it is applied.

Foray 48B also contains leftover bacteria food such as starches from potato, glucose or sucrose; proteins usually from corn but could be soy; and water. Other ingredients are sodium hydroxide, a pH adjuster used in chocolates, ice cream and margarine. Also contained is potassium phosphate, a yeast food used by the wine industry, and a thickening agent in cream cheese and ice cream. Other inerts are used but used in much smaller quantities. No petroleum products are used as carriers.

Who is responsible for determining that Foray 48B products can be used in Canada?

In Canada, pest control products must be reviewed and registered by the Pest Management Regulatory Agency (PMRA), a federal agency attached to Health Canada, before they can be sold or used. In the United States, this function is performed by the US Environmental Protection Agency (EPA).

Although the exact identity of the inert ingredients is considered a trade secret and not made public, they must be disclosed to the PMRA before the product can be sold in Canada. After reviewing toxicity information on the BtK and the inert ingredients in Foray 48B, both the Canadian PMRA and the US EPA have registered Foray 48B for aerial application over inhabited areas.

Is this the first time Foray 48B is being used?

No. This product has been applied on many occasions in the United States, Canada and elsewhere over the last 25 years. It has been applied previously by aircraft in British Columbia in the Okanagan, Lower Mainland and Vancouver Island, including the Saanich Peninsula.

Are there any risks associated with the Gypsy Moth?

Carefully considered, it is difficult to identify any situation that is risk free. There are well-documented cases of allergic reactions to the Gypsy Moth caterpillar in areas where this pest has become well established. Currently, levels of Gypsy Moth infestation on Vancouver Island are well below the level where it has produced outbreaks of illness.

Are there any risks associated with the Eradication program?

There is also some risk associated with the spray program. It is not possible to fly aircraft over inhabited areas without creating some risk to the people below. Although aircraft fly over inhabited areas every day, the additional flights required by the Gypsy Moth eradication program will involve some additional but small risk.

What should I do during the spraying?

Spraying will be done between the hours of 5:00 a.m. and 7:30 a.m. in April and 5:00 a.m. and 7:00 a.m. in May on three or four occasions. Spraying will only be done on days when the weather is suitable. The public will be advised in advance of the day on which spraying will occur. It is recommended that people stay indoors while the spray is being applied unless it is essential that they be outdoors. This is general advice for the public. No additional measures are required for any identifiable subgroups of the population. If an individual has a personal medical problem they believe may be made worse by the spraying they should seek the advice of their personal physician.

What could happen if I am exposed to the spray?

If you consume vegetables (produce), you have probably already ingested this bacterium. It is commonly used on commercial produce and may also be found on organically grown produce. In the environment the bacterium does not compete well with other organisms. In lakes and other surface water supplies, the organism does not survive long and the presence of BtK spores does not create a threat to water consumers. However, all surface water supplies should be disinfected to protect users from other naturally occurring disease-producing organisms present in the environment. In order to minimise general exposure to the skin, items such as playground equipment, benches, lawn chairs can be hosed off after spraying or covered before the spray.

The results of public health surveillance during the spray program in the Lower Mainland and elsewhere have not documented any increase in illnesses seen by physicians or in hospital emergency room visits that can be linked to spraying. It is clear that many people are strongly opposed to aerial spraying and hotlines set up during spray programs receive many calls from people who feel their health has been affected by aerial spraying.

Although the results of public health surveillance during previous spray programs have failed to link any increases in human illness to spraying of Foray 48B, a surveillance program will be in place during the 1999 spraying on Vancouver Island. This surveillance program will include some of the same activities that were part of previous surveillance programs. In addition, the surveillance done this year will incorporate a number of new measures to see if subtle effects on health that may have been missed can be detected

Do children, pregnant women or the elderly require special attention?

All the preceeding information applies to children, pregnant women and the elderly. If there are respiratory problems or allergies, staying indoors on each spray morning should minimize exposure to the spray droplets. Children should be discouraged from playing with any gypsy moth caterpillars if they find them, as their spiny hairs can cause welts or a patchy rash to occur which can persist for 4-5 days.

What about the immunocompromised?

Concerns raised about the potential harmful effects of organisms in individuals with an impaired immune system are not supported regarding Bacillus thuringiensis var.Kurstaki.

Can I leave my pets outside?

The greatest danger to pets left outdoors is that they may become frightened by the low flying aircraft noise and bolt into traffic or otherwise hurt themselves. If possible bring them indoors prior to spraying or secure them so that they will not harm themselves if startled

Summary

It is important to note that the action of BtK is very specific to caterpillars. After a thorough review of the toxicity of the Foray 48B product, including both the BtK and the inert ingredients, the U.S. Environmental Protection Agency and Health Canada's Pest Management Regulatory Agency have registered it for use in aerial applications.

Besides staying indoors while the spray is being applied in the morning, continued practice of simple good hygiene is recommended:

• Continue to wash hands during the day as usual (for example: following gardening, before preparing food and after going to the bathroom).
• Continue normal recommended maintenance procedures for home swimming pools.
• Day care centres and preschool facilities may choose to wipe over outdoor play equipment and cover sandpit to maintain usual attention to cleanliness
• Continue to ensure that all fruits and vegetables are thoroughly washed before eating.
  

The precautions mentioned above for people, including those with allergies, should prevent any health effects from Foray 48B.



This information sheet has been developed in consultation with the Provincial Ministry of Health,
the Capital Health Region and the Central Vancouver Island Health Region.
March 1999.

This page was updated on Rev. Mar. 24/99 and posted March 31, 1999.
Last update was on November 17, 2000