Module Information

The module will cover the basic morphology, physiology and life cycles of the major groups of parasitic protozoans, monogeneans, digeneans, cestodes, acanthocephalans, nematodes, (plant and animal parasitic) and parasitic arthropods, with special reference to those of medical or economic importance. Sites of parasitism will be first illustrated by a consideration of the vertebrate gut and how parasites are adapted for life in this specialized environment. There is a complex interaction between parasites and the immune systems of their hosts. Parasites have evolved a range of evasion strategies, including absorption of host antigen, antigenic variation, immuno-suppression and use of immunologically privileged sites. Immune evasion will be illustrated with examples from vertebrate and invertebrate hosts. Chemotherapy remains the most cost effective way of treating parasitic disease, but drug resistance is an increasing problem.
Parasites show a wide range of biochemical adaptations, many related to the micro-aerobic nature of their environment and the changes that occur during their life cycle. Biochemical differences between parasites and their hosts provide targets for rational chemotherapy, whilst differences between parasites and their free-living relatives can give an insight into the biochemical basis of parasitism. The organization of parasite genomes and some of the unique mechanisms of mRNA editing found in parasites will also be covered.
The discovery, development and mode of action of modern antiparasite drugs will be described, as will the mechanisms responsible for the evolution of drug resistance. The helminth nervous system is structurally simple, but biochemically complex and is an important target for anthelmintics.
The many problems involved in making a realistic assessment of the cost of parasitism or of measuring the impact of parasites on their natural hosts, will be discussed. Frequent attempts have been made to control parasites of humans, domesticated livestock and crops; the outcome of some of these control strategies will be evaluated. A summary of the current ideas on the evolution of parasites, the impact of parasites on the evolution of their hosts and of the concept of host-parasite specificity will be presented and discussed. The structure of parasites will be described in relation to the insight these studies provide into parasite survival both within the host and during the free-living stages. Life cycles, development and modes of transmission will include accounts of the importance of direct transmission, the role of vectors and intermediate hosts, zoonoses and reproductive potential (Ro). Patterns in the distribution of parasites will be described and the mechanisms responsible for generating those patterns evaluated.
The module will include a seminar discussion on a recent research publication that will form the basis of a compulsory question in the written examination. The module concludes with invited research seminars from researchers from the IBERS Parasitology group.