08.12.2023_Phase1_Parasitology_ Introduction_and_Classification.pptx

PARASITOLOGY INTRODUCTION & CLASSIFICATION PROF. DR. SİBEL ERGÜVEN ([email protected]) TERMINOLOGY SYMBIOSIS “LIVING TOGETHER”. - The relationship between two living things (animals). Two living things live together and involve protection or other advantages to one or both partner. - S...

PARASITOLOGY INTRODUCTION & CLASSIFICATION PROF. DR. SİBEL ERGÜVEN ([email protected]) TERMINOLOGY SYMBIOSIS “LIVING TOGETHER”. - The relationship between two living things (animals). Two living things live together and involve protection or other advantages to one or both partner. - Symbionts : Organisms living together • Commensalism • Mutualism • Parasitism* COMMENSALISM GUEST “+” HOST “0” • One gain advantage from the association at least not damage to the other. • An association in which the commensal takes the benefit without causing injury to the host. (ex: Entamoeba coli in intestinal lumen of host) COMMENSALISM “EATING AT THE SAME TABLE”. - Both partners are able to lead independent lives, but one may gain advantage from the association when they are together and least not damage to the other. Fig. A female pea crab in the mantle cavity of its mussel host. The crab does not damage the mussel and uses its shell purely for protection MUTUALISM GUEST “+” HOST “+” • Beneficial to both living things. • None of the partners suffers any harm from the association • Both partners are metabolically dependent upon each other and one cannot live without the help of other MUTUALISM - An association which is beneficial to both living things. Fig. A selection of ciliates from the rumen. The rumen contains enormous numbers of ciliates that break down cellulose in the feed. PARASITISM GUEST “+” HOST “-” • Para: beside • Sitos: grain of food • Beneficial to one partner and harmful to the other partner. The former is called parasite, the latter is called host. • Parasite benefits host is hurt! Parasite: a living organism which takes its nourishment and other needs through contact with another species. The host: is an organism which supports the parasite which later develops diseases. Medical parasitology: “the study and medical implications of parasites that infect humans” MEDICAL IMPORTANCE OF PARASITES Many of these parasites are causative agents of major public health problems of the world. Recent estimates of prevalence of parasites in the world are: Disease Category # Human Infections Deaths per year Roundworm Ascaris lumbricoides 1.2 billion 60,000 Whipworm Trichuris trichiura 795 million 10,000 Hookworms 740 million 65,000 Filarial worms 657 million 20,000 to 50,000 Malaria 300- 660 million 1-2 million Schistosomes 200 million 20 million Ameba Entamoeba histolytica 50 million 40,000 Liver fluke Clonorchis sinensis 20-30 million ? These parasites cause untold and43,000 death in the world Chagas’ Disease Trypanosoma 15 suffering million today. cruzi TYPES OF PARASITES (LOCATION) Ectoparasite Endoparasite • “a parasite that lives • «a parasite that lives on the external surface within another living of another living organism» – e.g. organism” – e.g. lice, Plasmodium spp., ticks Giardia 2.5 mm ENDOPARA SITE THE TYPES OF PARASITES (NEED OF HOST) Obligate parasite: completely dependent on the host during a segment or all of its life cycle All or most of their life cycyle are parasitic ex: Plasmodium THE TYPES OF PARASITES (NEED OF HOST • Facultative parasite: Exhibits both parasitic and non parasitic modes of living • Can live parasitic for a limited period • ex: Strongyloides stercoralis THE TYPES OF PARASITES (NEED OF HOST) • Accidental parasite: Parasite attacks an unnatural host and survives but may or may not complete life cycle. • Normally free living can survive within a host when they are accidentally taken. • ex: Echinococcus granulosus ECHINOCOCCUS GRANULOSUS • After ingesting onchospheres in eggs penetrate the intestinal wall and are carried in the circulatory system • Most frequently filtered out in the portal capillaries • If they pass liver they can invade the lungs, brain and long bones and also other organs • A slow growing cysts develops TYPES OF PARASITES (NEED OF HOST) • Erratic parasite: Parasite that wanders into an organ in which it is not usually found. • ex: Entamoeba histolytica reaching the liver TYPES OF PARASITES (NEED OF HOST) • Opportunistic parasites: Occurs in immunocompromised patients do not cause diseases in immunucompetent people or cause mild disease • ex: Cryptosporidium TYPES OF HOST Definitive host: • “the organism in which the adult or sexually mature stage of the parasite lives” -e.g. HumanTaenia saginata Intermediate host: • “the organism in which the parasite lives during a period of its development only” • Larval forms lives -e.g. Cattle Taenia saginata TYPES OF HOST Reservoir host Harbors the parasite for a long time act as a source of infection in the environment. Non human host Ex: Leishmania - dogs TYPES OF HOST Accidental host A host that is under normal circumtances not infected with the parasite Ex: Humans in Echinococcus granulosus TERMINOLOGY Monoxen parasite having only one host for all its life cycle - e.g. Trichomonas vaginalis Heteroxen parasite having more than one host for its life cycle -e.g. Fasciola hepatica Pathogen: A parasite which is able to produce disease. Virulence: Refers to the degree of pathogenecity. Infection: The presence of parasite in or on the tissues of the host. Infestation: The presence of arthropodes on the skin of the host. Anthoponosis: parasitic infection is found in man alone Zoonosis: a parasitic disease in which an animal is normally the host - but which also infects man Vector: “a living carrier (e.g.an arthropod) that transports a pathogenic organism from an infected to a non-infected host”. Biologic vector: A vector which is absolutely necesarry for the evolution parasite. eg: Female Anopheles of mosquito that transmits malaria Mechanical vector: A vector which just carry the parasite. eg: house fly (Musca domestica) BIOLOGIC VECTOR THE SOURCE OF THE INFECTION • Persons who have parasites in their body and show Patie clinical symptoms. nt • Persons who have parasites in their body, not show Carri symptoms. er Reserv oir host • Animals that harbors the parasites in nature THE ROUTES OF TRANSMISSION I Congenit al transmis sion Contact transmis sion • From mother to infant---Toxoplasma gondii • Direct contact---Trichomonas vaginalis; • Indirect contact---Ascaris lumbricodes • The infectious stage of parasites contaminated food ---metacercaria of F. hepatica on water cress Food • The meat of the intermediate hosts containing transmis infectious stage of parasites ----larvae of T. sion saginata in beef THE ROUTES OF TRANSMISSION II Water transmissi on Soil transmis sion Arthropo d transmis sion • Drinking or contact of the water contaminated with the infectious stage of parasites • Contact with the soil which is contaminated with certain stages of parasites • Vectors of certain parasitic diseases THE AVENUES OF INVASION Digestiv e tract • Most common avenue of entrance (Food/ Water transmission) Skin • Infective larvae perforate skin and reach to body and establish infection (soil/ water transmission) Bloo d • Bloodsucking insects containing infective parasites bite the skin and inject parasites into human blood (Arthropod transmission---malaria). EFFECTS OF PARASITES ON THE HOST Depriving the host of essential substance • Hook worm suck blood anemia Mechanical effects of parasites on host • Ascaris perforation/obstruction EFFECTS OF PARASITES ON THE HOST Toxic and allergic effect • Entamoeba histolyticaproteolytic enzyme necrosis Deprivation of nutrients • Parasite antigenimmune system immune response Allergy/hypersenstivity/anaphylaxis EFECTS OF PARASITES ON THE HOST • Tissue damage • Gastrointestinal • Respiratory • Neurologic • Cutanenous symptoms • Eosinophilia MEDICAL PARASITOLOGY Protozoa Helminths Arthropods CLASSIFICATION AND STRUCTURE • The parasites of humans are classified within the kingdom Animalia and are separated into two subkingdoms, Protozoa and Metazoa. • The Protozoa are animals whose life functions occur in a single cell. • The Metazoa are multicellular animals. Protozoa: unicellular organisms, e.g. Plasmodium (malaria) Metazoa: multicellular organisms, e.g. helminths (worms) and arthropods (ticks, lice) The genus starts with a capital letter and the species is always written in italics, e.g. Plasmodium falciparum, Giardia lamblia Flagellates Sarcomastigophora Amoebae Ciliophora Protozoa Apicomplexa or Sporozoa Parasites Microspora Helminths Cestodes Platyhelminths Trematodes Nemathelminths Chilopoda Metazoa Pentastomida Arthropods Crustacea Arachnida Insecta Nematodes         Protozoa Eukaryotic Unicellular Vegetative form is a trophozoite Asexual reproduction by fission, budding, or schizogony Sexual reproduction by conjugation / syngamy Some produce cysts DNA exists as chromosomes in nucleus Microscopic PROTOZOA • Small • Unicellular organisms • Contains nucleus and functional organelles • Reproduce quickly • May have asexual and/or sexual phase in the host and/or vector ECTOPLASM • Movement • Ingestion of food • Excretion • Respiration • Protection ENDOPLASM • Nutrition • Reproduction NUTRITION • Nonphotosynthetic • Osmotrophs:Absorbe dissolved nutrients directly through their cell membrane. • Phagotrophs: Feed by engulfing soluble organic material or solid particles, forming intracytoplasmic food vacuoles. • Ectoplasm takes nutrients by means of pseudopodia. • Excrete enzymes that degrade nutrients into soluble substances and absorbe them. • Cytostome: Taking nutrients. Forms of Protozoa • Cyst • Trophozoite • Trophozoite – living, motile, reproducing form responsible of the infection • Cyst – non-active, non-motile form, responsible of the transmission MOTILITY ORGANELLES • Flagella • Cilia • Pseudopodia MOTILITY ORGANELLES • Flagella • Cilia: Ingestion of food. Sensory organs. • Pseudopodia: Ameboid motility. False-feet Axostyle: Central supporting rod. SINIF: ZOOMASTIGOPHOREA Leishmania Giardia Trichomonas Promastigote • Axoneme • Blepharoblast takes place on outer side of nuclear membrane. • Parabasal body • Kinetoplast Binary fission Flagellum formation Energy for motility • Undulating membrane nucleolus AMEBOID MOTILITY Amiplerin mitokondrileri? REPRODUCTION Asexual reproduction 1. Binary fission 2. Schizogony 3. Budding Sexual reproduction 4. Conjugation 5. Syngamy Paramecium Binary fission Schizogony (budding) Conjugati on Syngamy HELMINTHS HELMINTHS •Multicellular •Possess specialized organ systems •Complex life cycle •Visible to the naked eye •Coated with “cuticula” •Egg, larvae, adult Egg Larvae Adult • No intermediate host: Directly from infected to uninfected. • No intermediate host: Resting on soil for a time. • Intermediate host or hosts: Intestinal tract Helminths Liver Lungs Blood Skin Lymphatics Other organs I. PLATYHELMINTHS • Flatworms 1)The trematoda: flukes 2)The cestoda: tapeworms II. NEMATHELMINTHS • Round worms Nematoda (round worms) Adults • Non segmented, cylindirical • Covered with an acellular “cuticle” • Separate sexes • Complete digestive tract • Excretory and nervous system • Humans are the definitive host NEMATODE Ascaris lumbricoides HELMINTHES Trematodes Nematodes (Round Worm) Unsegmented Round Separate sexes Complete GIS (Flatworm Fluke ?) Unsegmented Leaf-like (excpt Schisto) Hermaphroditic (excpt Schisto) Eggs with lids (exp Schisto) Min two hosts, one is snail Have 2 suckers Blind gut Cestodes (Tapeworm) Segmented Scolex, neck, proglottids Hermaphroditic Have suckers / hooks Eggs have hooks & no lids (excpt Dpyllo) No GIS TREMATODE Vücut genellikle düz ve yaprak şeklinde Büyüklükleri bir kaç mm-cm Güçlü çekmenler Dolaşım sistemi ve duyu organları yok İyi gelişmemiş bir sindirim kanalı Çoğunluğu hermafrodit THE PREVENTION MEASURES OF THE PARASITIC DISEASES • Controlling the source of the infection. ----Treatment of the patients, carriers and reservoir hosts. • Intervention at the routes of transmission ----Managing feces and water resource,controlling or eliminating vectors and intermediate hosts. • Protecting the susceptible hosts. ----Paying attention to personal hygiene, changing bad eating habit, taking medicine.