Parasitology Lab 13

Introduction to Parasitology

• Parasitology is the science that focuses on the study of parasites, their hosts, and the relationships between them.
• Parasites are organisms that live in or on another organism (the host) deriving food and shelter and causing harm to that host.

General Characteristics of Parasites

• Depend on a host organism for survival
• Usually smaller than their host
• High reproductive rate
• Complex life cycles
• Evasion of the host's immune system
• Feed by hooks, suckers, claws, teeth, or specialized mouthparts

General Terminology of Parasitology

• Endoparasites: live within the host causing infection
• Ectoparasites: live on the external surface of the host causing infestation
• Opportunistic parasite: produces disease only in immunodeficient hosts
• Intermediate host: in which the parasite lives during its larval stage or asexually reproducing form
• Definitive host: in which the adult or sexually reproducing form of the parasite lives
• Vector: usually an arthropod that transmits parasites (or other pathogens) from infected organisms to other hosts

Types of Parasites

Protozoa

• Single-celled organisms
• Either free-living or parasites
• Lack a cell wall
• Generally heterotrophic
• Divide by binary fission, schizogony, or budding

Protozoa Classification and Examples

• Mastigophora or Flagellated protozoans:
  • Have flagella for locomotion
  • Body is covered by a cuticle or pellicle
  • Reproduction is by binary fission
  • Examples: Trypanosoma, Trichomonas, Giardia, Leishmania
• Sarcodina or Amoeboids:
  • Movement is by pseudopodia
  • Pellicle is absent
  • Reproduction is by binary fission and cyst formation
  • Examples: Amoeba, Entamoeba, etc.

This quiz covers the introduction to parasites and parasitology, the science that studies parasites. It is designed for first-stage students at the College of Dentistry.