ABSTRACT
Baylisascaris is a genus of roundworms, which occur in the intestines of a number of mammals. There are nine species, each of which has a small number of mammal species that serve as its reservoir hosts. In North America, raccoons are the denitive host (i.e., the host in which the parasite reaches sexual maturity and reproduces) for Baylisascaris procyonis; skunks for Baylisascaris columnaris; black, grizzly, and polar bears for Baylisascaris transfuga; mustelids for Baylisascaris devosi; and rodents for Baylisascaris laevis. In denitive hosts, female roundworms reach sexual maturity and produce eggs that are shed in the animal’s feces. All of these roundworm species can potentially infect humans, but B. procyonis is the only one known to cause serious diseases in humans; hence, this chapter will focus on raccoon roundworms (Figure 28.1).
