Key terms

• Commensalism


  Least intimate of relationships where one or both species benefit e.g. microorganisms on skin - transport, cleaning, protection
• Mutualism


  An association where both partners benefit e.g. protozoa in gut of horse and fore stomach ruminants
• Why study parasitism?
• Implications to human and animal health and welfare. Millions of pounds spent annually in prevention and control. Ubiquitous nature of parasites means they will never be eradicated completely - can only aim to minimise damage by understanding them and using products to manage to maintain parasites.
• What damage do parasites do?
• Parasites


  • Affect digestion- either helpfully or can block gut and eat food and take nutrients (physical barrier)
  • Diseases - they can infect the animal they are using as the host
  • Can eat cells, and breakthrough organs creating a wound and potentially sepsis
• Host


  The organism that the parasite lives on or within
• Definitive host


  Host that parasite reproduces
• Intermediate host


  No reproduction, used as a process for parasite to change (cycle)
• Life cycle


  Egg to adult laying larvae whole stage of transforming
• Direct life cycle


  Definitive host where reproduction occurs that the affects another definite hose
• Indirect life cycle


  From definite host to something else and back to definite host (usually involving eating)
• Pathogenesis


  What changes in the body, what damages happen to body internally
• Paratenic host


  Carrier or transport host; parasite remains alive, but will not grow
• Clinical signs


  Symptoms of damage (jaundice, bottle jaw) what we see externally
• Transmission


  How it gets from one host to another
• Epidemiology


  Describing how disease occurs and where it comes from distribution of disease, how its moving, how its spreading
• Zoonosis


  Something that is transmissible between animals and humans
• Parasite


  An animal that lives for an appreciable part of its life on (ectoparasite) or in (endoparasite) another organism, the host, and is dependent on the host and benefits from the association at the expense of the host