Parasitology - Introduction and Basic Principles PDF
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Uploaded by LawfulStarfish
Dr. Muhammad Nauman Zahid
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This document provides an introduction to parasitology, covering definitions, types of parasites, and their classification. It also touches upon the significance of studying parasites, their symbiotic relationships, and related terminology. The content is likely part of a lecture or educational resource, suitable for undergraduate-level study of biology.
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Parasitology Dr. Muhammad Nauman Zahid [email protected] Introduction Parasitology What are parasites and what do they cause? Parasites Word parasite derived from the Greek and means literally “situated beside” A living organism which gets nourishment from another living organi...
Parasitology Dr. Muhammad Nauman Zahid [email protected] Introduction Parasitology What are parasites and what do they cause? Parasites Word parasite derived from the Greek and means literally “situated beside” A living organism which gets nourishment from another living organism where it lives is called parasite. Parasites-live on or within some other organisms (host) Shelter Food Reproduction Why do we study parasites? o Parasites provide unique examples of biological phenomena not found in free-living organisms o Medical importance ✓ Veterinary importance o Economic importance Why do we study parasites? Cause disease-animals and humans Transmit disease-act as vector Debilitating effects-prone to other diseases Major Groups of Parasites ✓Protozoan (Protozoolgy) Single celled eukaryotes Malaria, Giardia, Trichomonas ✓ Helminths (Helminthology) Multicellular Flukes, tapeworms, roundworms ✓ Ectoparasites (Entomology) Multicellular Live outside the body Insects (mosquitoes, lice, and fleas) & Arachnids (ticks and mites) Parasitism and its Types Two species association- one species ( parasite) lives on or in second species (host). Symbiosis- is any type of a close and long- term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasitic. Example: Termite and their protozoa Parasitism Commensalism – one benefits while the other is neither harmed nor helped. Example: Non pathogenic protozoa, mites travelling on fly Mutualism – both benefits from the relationship. Example: Ruminant and their microflora A large percentage of herbivores have mutualistic gut flora to help them digest plant matter, This gut flora is made up of cellulose- digesting protozoans or bacteria living in the herbivores' intestines. Coral reefs are the result of mutualisms between coral organisms and various types of algae which live inside them. Parasitism Parasitasis –one potentially pathogenic but not cause sign/symptoms of the disease Parasitosis- one injure the other cause sign/symptoms and disease lesion Classification of parasites Endoparasite -within body of host e.g. Entamoeba histolytica, Ascaris lumbricoides, etc. Ectoparasites -on the body of host e.g. ticks, mites, lice Erratic- invade body organs that they do not normally invade e.g. E. histolytica is a good example of erratic parasites. Typically, this anaerobic parasite is found in the gastrointestinal tract where they cause amoebiasis (bloody diarrhea). However, the parasite has been shown to wander and invade such organs as the liver and lungs in human beings. Classification of parasites Obligate parasite (who must spend some part of their life cycle in or on host, e.g. plasmodium). Facultative parasite (may be free living but can obtain the nutrition from hosts too). E.g. Nargleria Fowleri Accidental parasite (when parasite attacks unnatural host). E.g. Rat tapeworm Aberrant parasite (when the parasite comes to a site, during migration where it cannot live or develop further). E.g. For example, the tapeworm Taenia solium may migrate to the brain and remain there unless removed via an operation. Terminology Infection-disease condition due to endoparasites Infestation-disease condition due to ectoparasite Parasitemia-parasite in blood circulation Pathogenic-disease causing Pathogenesis-pattern of disease occurrence Immunity-ability to ward off a disease Terminology Anthroponoses-human diseases can be transmitted to animals Zoonosis-animal diseases may be transmit to human Epidemic-disease effect large no. of human, spread rapidly Epizootic-disease effect large no. of animals Epizoic-living on the surface; skin parasite Incidence-no. of cases of an infection occur during a given period of time in relation to population Prevalence-no. of cases of an infection occur at any time in a population Terminology Virulence-relative infectiousness Juvinile stage- sexually mature adult stage Haematophagus-eating of blood by a parasite Host specificity-restriction of parasite to one or more host Hyperparasitisim-presence of parasite in/on other parasite