Introduction to Parasitology Jafari R Isfahan University of Medical Sciences

Human disease agents a-Viruses b-Prokaryotes c-Eukaryotes

Symbiosis Types of life Merriam-Webster dictionary “The relationship between two different kinds of living things that live together and depend on each other”

Symbiosis Commensalism Mutualism Phoresis Parasitism

Commensalism “A relationship where one species obtains food or shelter from the other species. Does not harm or help the other species”

Mutualism “relationship where both species benefit from the relationship”

Phoresis “The phoront, is mechanically transported by its host. Neither organism is physiologically dependent on the other”

Parasitism “A relationship between two species in which one species (the parasite) nourishes itself to the disadvantage of the other species (the host)”

Terminology Parasite: an organism which lives in or on another organism (its host) and benefits by deriving nutrients at the other's expense. Host: an animal or plant on or in which a parasite or commensal organism lives Parasitology: study of parasites, their hosts, and the relationship between them Vector: an organism, typically a biting insect or tick, that transmits a disease or parasite from one animal or plant to another.

Types of parasites Ectoparasite: e.g. fleas, Ticks Endoparasite Facultative-p Obligate-p Permanent-p Temporary-p Accidental-p Abberant-p Types of parasites Ectoparasite: e.g. fleas, Ticks Endoparasite: e.g. malaria Facultative parasite: e.g. free living Amebae Obligate parasite: e.g. filaria Permanent parasite: e.g. intestinal worms Temporary parasite: e.g. mosquitoes Accidental parasite: e.g. Dicrocoelium Abarent parasite: e.g. Toxocara

Types of hosts Definitive host: e.g. Anopheles for malaria Intermediate host: e.g. human for malaria Reservoir host: e.g. Beaver for Giardia Paratenic host: e.g. 2nd Fish for Diphyllobothrium

Vector - Mechanical Vector - Biological Vector A vector that conveys pathogens to a susceptible individual without essential biologic development. E.g. the transfer of septic organisms on the feet or mouth parts of the housefly - Biological Vector A vector that conveys pathogens to a susceptible individual with essential biologic development E.g. the transfer of the deadly disease malaria by mosquitoes

Life cycle Zoonotic A disease that can be passed between animals and humans Anthroponotic An infection in which a disease causing agent carried by humans is transferred to other human or even animals

Terminology Infestation Infection: Disease Super infection Re infection Retro infection Auto infection Disease

Source of infection or infestation Soil born Water born Food born Vector born Fomite Zoonosis

Portal of entry Mouth : - Water Skin : - from the soil - Food Skin : - from the soil - from the water - by blood-sucking arthropods Inhalation: of air-born eggs or cyst Transplacental ( congenital ) Transmammary ( milk ) infection Sexually transmitted infection

Systematic classification of living things Animalia Kingdomسلسله => Metazoa, Protozoa Phylumشاخه Classرده Orderراسته Familyخانواده Genusجنس Speciesگونه Strain سویه

Kingdom - Metazoa - Protozoa Using light microscope; (Amebae, Flagellates, Ciliates, Sporozoea) Using electronic microscopic; (Sarcomastigophora, Apicomplexa, Microspora) - Metazoa Helminthes; Nematoda, PlatyHelminthes (Trematoda,Cestoda) Acanthocephala

Protozoa Protoplasm Cytoplasm Ectoplasm Endoplasm Nucleoplasm

Ectoplasm Function Endoplasm Function 1-Protection of the organism 2- Locomotor aparatus 3-Food ingestion 4- Respiration 5-Discharge of metabolic wastes Endoplasm Function Containing ; mitochondria, golgi, Glycogen vacuoles & chromatidal bodies, Food vacuoles, ... Food synthesis Excretory vacuoles (collection of fluid wastes) Contractive vacuoles (maintain osmotic pressure)

Vital function -Locomotion: locomotory organelles; 1 Pseudopodia 2 Cilia 3 Flagellum 4 Undulating membran 5 without locomotory organell (gliding movement) -Respiration: 1- aerobic (blood & tissue protozoa) 2- micro-aerophilic (intestinal protozoa) -Nutrition: liquid absorption cell mouth (cytostom) pinocytosis phagocytosis

Reproduction of protozoa Asexual 1- Binary-fission : (Amaebae) 2- Endodiogeny : Coccidia 3- Schizogony (merogony): Plasmodium Sexual 1- Syngamy: Free-flagellates 2- Sprogony : Malaria parasites 3-Conjugation: Ciliata

Life cycle of protozoa Trophozoite transmission: (e.g.; Enta. Gingivalis) Cyst transmission: Entamoeba

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