Medical Parasitology

Abstract

Preface: Virtually every organism serves as the host for a complement of parasites.Parasitism is so common that it is rare to find classes of animals withoutmembers that have adopted a parasitic mode of living. Evidence gained fromvarious archeological studies indicates that parasitic diseases existed inprehistoric human populations. Since there is no evidence to suggest thatour long and intimate association with parasites will ever end, it seemsreasonable to propose that the study of human parasites warrants someconsideration. However, the study of parasites is a very challenging endeavor.Host-parasite associations involve complex biochemical, physiological,behavioral and ecological adaptations that very likely have co-evolvedindependently and on many different occasions. These complex and intimateinteractions are continually evolving as counterstrategies in both host andparasite populations, thus limiting our ability to adequately study the factorsthat influence immune competency, parasite virulence, adaptability,epidemiological diversity, and drug resistance. However, the most importantchallenge facing parasitologists derives not from technical or experimentaldifficulties, but from the fact that most of the parasitic diseases that have amajor impact on humans are largely associated with the rural poor in tropical,developing countries, which typically attract little interest from strictlycommercial enterprises and other agencies that fund research.Today, the extent of human suffering due to parasites is incalculable andintolerable. The physiological, pathological and economic problems causedby parasites are global concerns, and it is imperative that health professionalshave some understanding of the complex interactions between humans andtheir parasites. Inexplicably, many medical schools fail to offer a curriculumthat contains a formal course in parasitic diseases, or, in some cases, even toprovide a single lecture on the topic. It is our belief that the collaborativeefforts of parasitologists and medical professionals are urgently needed toimprove efforts to treat parasitic infections. Parasites of Medical Importance isdesigned primarily for health professions and students interested in pursuingcareers that will address the growing threat current and emerging parasiticdiseases pose to the global population. In preparing this textbook we assumedthat it would be a first exposure to the study of parasites for those who havehad little or no formal instruction in parasitic diseases. Thus, emphasis hasbeen placed on parasite life cycles and host pathology, with limited discussionsof parasite morphology, taxonomy, and pharmacological treatments.The authors assume full responsibility for omissions or any mistakes thatappear in the book, and will correct such issues in subsequent editions.