Human Health Effects Resulting from Exposure to Bacillus thuringiensis Applied during Insect Control Programmes

Abstract

Products based on Bacillus thuringiensis (Bt) such as Foray 48B, which contains Bt kurstaki strain HD-1, must meet rigorous standards required by the US Environmental Protection Agency, the US Food and Drug Administration, the Canadian Pesticide Management and Regulatory Agency, and Health Canada, before they are approved for commercial use in Canada and the US. These agencies consider Bt-based products to be neither toxic nor pathogenic to mammals, including humans. Despite these approvals, there remains widespread public concern about negative health effects associated with aerial applications of Btk during insect control programmes. Major health impact assessment studies in the US and Canada suggested there were no negative short-term human health effects associated with aerial applications of Foray 48B. A similar health impact assessment conducted in New Zealand reported short term irritant effects and some worsening of pre-existing conditions such as allergies and asthma. These findings warrant further investigation following aerial applications of commercial Bt products in populated urban areas.