26. Defence against infection: the immune system
26. Defence against infection: the immune system
- Gillian Pocock, Gillian PocockSenior Lecturer in Clinical Science, Canterbury Christ Church University, Canterbury, UK
- Christopher D. RichardsChristopher D. RichardsEmeritus Professor of Experimental Physiology, Division of Physiology, Pharmacology and Neuroscience, Faculty of Life Sciences, University College London, London, UK
- and David A. RichardsDavid A. RichardsAssociate Professor, Department of Basic Pharmaceutical Sciences, Husson University School of Pharmacy, Bangor, Maine, USA
Abstract
This chapter discusses how animals inevitably come into contact with other organisms as they move through their environment to feed and reproduce. It describes some of the organisms that may attempt to invade the body and may live in harmony with the host. When this is of benefit to both the host and the other organism, it is known as mutualism, while it is called commensalism if the association is neither beneficial nor harmful. The chapter analyses the relationship known as parasitism when the presence of the invading organism compromises the health of the host. It highlights the various ways in which the body defends itself against infectious diseases that are caused by bacteria, fungi, viruses, protozoa, and worms of various kinds.
