The American cockroach was introduced to North America from Africa as early as 1625 (Bell and Adiyodi 1981). It is the largest in the world, and is second in population size only to the German cockroach. At least 22 species of pathogenic human bacteria, viruses, fungi, and protozoans, as well as five species of helminthic worms, have been isolated from field collected American cockroaches (Rust et. al. 1991).