Parasite Classification & Medical Importance PDF

Summary -Parasite: a living organism lives on/in another living organism (host) for food + shelter, & dose harm to it (host). Parasites (Eukaryotic) are Protozoa, Helminth & Arthropoda -Parasitism: a living organism gains food & shelter on expanse of another -Life cycle: Direct: need one host [No...

Summary -Parasite: a living organism lives on/in another living organism (host) for food + shelter, & dose harm to it (host). Parasites (Eukaryotic) are Protozoa, Helminth & Arthropoda -Parasitism: a living organism gains food & shelter on expanse of another -Life cycle: Direct: need one host [No I.H] - Indirect: need more than one host [Require I.H(s)] -Basic parasite life cycle stages in human (Infective stage, pathogenic stage & diagnostic stage) [slide] Host: Organism harbors a guest organism (parasite) [Serves as source of food & habitat to a parasite] Definitive/Final Host (DH): host harbors adult (mature) (sexually reproducing) stage of parasite Intermediate Host (IH): host harbors Larva (immature) (asexually reproducing) stage of parasite Paratenic Host: host harbors parasite & play role in parasite life cycle BUT in/on which no development of parasite occurs (arrested development) i.e. host in which parasite end blindly, but parasite can continue development in a suitable host. Reservoir Host (RH): an animal harbors same parasite species & stage as man SO maintain parasite in nature & act as a potential source of human infection. Vector: an arthropod carries parasite from host to host -Opportunistic Parasite: Parasite produces disease only in immunocompromised -Source of parasitic infection: Environment (food, soil, water) Hosts (Human [case/carrier]/animal/Arthropoda [vector]) -Mode of transmission of parasitic infection: Acquired (6) – Congenital [slide] -Faeco-oral Parasites/Food-borne Parasites (FBP)[Most common] (Occurrence/entry of Parasites in Foods & water) - Zoonotic diseases: Diseases pass from animal to human (Directly: Eating animal tissue/products Contact with infected animals OR Indirect via vector) Prevention & Control Hosts (Reduce sources): Treatment of cases/carriers-Control of vector & animal (reservoir…) hosts Health Promotion (Interrupt transmission): a) Health education b) Environment sanitation c) Personal prophylaxis Medical importance of Arthropods (cont.) II. Vectors = disease transmission 1. Mechanical transmission: passively carrying disease without development or multiplication a. Indirect= by contamination: Non-biting arthropod carry microorganisms on its mouth parts, legs or hairs e.g. house fly 2. Biological transmission: microorganism undergo changes (develop/multiply) in Arthropoda i.e arthropod part of its life cycle e.g. a. Propagative: organism multiply in vector without cyclic changes e.g. Y. pestis in flea, yellow fever in Aedes b. Cyclo-developmental: organism develop in vector without multiplication e.g. MF of W.bancrofti in Culex b. Direct= by inoculation: Biting arthropod carry microorganism on its mouth parts during feeding e.g stomoxys (Trypanosoma rhod.) c. Cyclo-propagative: organism multiply & develop in vector e.g.Leishmania in sand fly, Plasmodium in Anopheles d. Transovarian= organism transmitted from infected mother to offspring through the eggs e.g. Tick transmitted disease e. Trans-stadial = organism transmitted from stage to stage e.g Scrub typhus organism (Rickettsia orientalis) pass from larva→nymph→adult→next larva of Trombicula akamushi mite I - Taxonomic Classification of parasites 1. PROTOZOA 2. HELMINTH i Unicellular (Protozoa) Multicellular (Metazoa) ii Multiply within host Do not Multiply within host iii 3. ARTHROPODA Multicellular (Metazoa) ? (except Strongyloides-trichinella?) No No i) Amoebae i) Platyhelminth (flat) (e.g. Entamoeba histolytica) Have Exoskeleton i) Insecta: a. Diptera: Flies Mosquitoes a) Trematoda/Fluke (leaf like) (e.g. Fasciola spp. ii) Flagellates Schistosoma spp.) (e.g. Giardia lamblia) b. Siphonaptera: Fleas c. Anoplura: Lice b) Cestoda (tape) ii) Ciliates d. Hemiptera: Bugs (e.g.Taenia saginata) (e.g. Balantidium coli) ii) Sporozoa ii) Nematoda (round) (e.g. Plasmodium spp. [Malaria] Toxoplasma gondii) ii) Arachnida: Ticks Mites (e.g. Sarcopties scabiei) e.g. Ascaris lumbericoides) iii) Crustacea: e.g. Cyclops Medical Helminthology Medical Protozoology Medical Parasitology Ayman A. El-Badry Medical Entomology Summary 9 summody Define: Protozoa (Unicellular-Multiply within host), Helminth (Multicellular- Usually not multiply within host), Arthropoda (Multicellular Exoskeleton [invertebrate] – Jointed limbs [Segmented body]). definition Medical importance of Arthropoda: cause disease (e.g. Scabies by Sarcoptes scabiei , bites of mosquitoes, fleas, bugs & lice) – Vector (mechanical –Biological [Propagative- Cyclo-developmental- Cyclo-propagative; define] Types of protozoa according to motility (e.g. amoebae, flagellates, ciliates, sporozoa) Types of Helminths according to motility shape (Trematoda [Flat, leaf shape-unsegmented-Hermaphrodite], Cestode [Flat, tape shape-segmented- Hermaphrodite], Nematode [round/cylindrical-unsegmented-Unisex]), parasites Examples of parasites: genus & species, protozoa/helminth/Arthropoda, habitat and mode of transmission 1. 2. 3. 4. 5. 6. Schistosoma haematobium, mansoni (one Trematoda, helminth) Ascaris lumbericoides (one nematode helminth) Giardia lamblia (one flagellate, protozoa) Entamoeba histolytica (one amoebae, protozoa) Malaria/ Plasmodium species (one sporozoa, protozoa) Mosquito, Flies, Flea, Bugs, Lice (Insect)/Sarcoptes scabiei (Arthropoda)