Humans and animals are frequently infected with at least one species of parasite and most also harbor other parasitic or infectious agents. The interactions between these agents are often subtle and are subsequently ignored by parasitologists, ecologists and immunologists. This volume explores these interactions in detail, with particular emphasis on their immunological and ecological aspects. Included are contributions on parasitic infections and AIDS, and the problems of treating patients with multiple infections. This book is of interest to researchers and clinicians dealing with parasitic, viral, or bacterial infections in the laboratory or in the field.