38th Annual Meeting of the Society for Invertebrate Pathology

There is considerable evidence that Bacillus thuringiensis (Bt) is neither toxic, nor pathogenic to mammals. None-the-less, applications of Bt sprays in populated urban centers generates considerable public concern about the impact of exposures to Bt on human health. Aerial applications of Foray 48B, which contains (Bt subspecies kurstaki, strain HD1 (Btk HD1), were applied to control the European gypsy moth (Lymantria dispar) in Victoria, British Columbia, Canada, in 1999. An assessment of the health impact of Foray 48B was also conducted during this period. Environmental and human samples, collected before and after aerial applications of Foray 48B, were analyzed for the presence of Bt HD1-like bacteria. Molecular methods were used to determine the identity of over 11,000 isolates from environmental and human samples. Several health indicators, including an assessment of the impact of the spray on asthmatic children, we measured. Results of the studies suggest that Bt HD1-like bacteria were present both in the environment and in the human population of Victoria prior to aerial applications of Foray 48B, and that the spray had no detectable adverse effect on the human population.