Introduction Parasitology Parasitology Department Medical Faculty of Universitas Sumatera Utara
Parasite Definition: Dependence of one living organism on another 2
CLASSIFICATION (based on habitat) t) Ectoparasite: parasite that lives on the outer surface of its host ex. Pediculus humanus capitis Endoparasite: parasite that t lives inside id its host ex. Ascaris lumbricoides Parasite facultative: parasite which can be life as parasite or free living ex. Strongyloides stercoralis 3
Classification Parasite obligate: organism that is physiologically dependent on establishing sh a symbiotic relationship with another Ex. Enterobius vermicularis Accidental parasite (spurious): parasite enter or attach to the body of a species of host; different from its normal one ex: Toxocara spp 4
Classification Periodic parasite: parasite that half of its lifecycle as a parasiter. Ex. Hookworm Permanent parasite: parasite that all of its lifecycle as a parasiter. Ex. Plasmodium spp. Monoxen parasite: parasite can life only one host. Ex. Enterebius vermicularis Polyxen parasite: parasite can life more than one host. Ex. Schistosomatidae 5
Terminologi in the Parasitology: Host : organism as a living place for parasite Definitive host: host in which a parasite achieves sexual maturity Reservoir host: animal that life same species parasite with human and can happen lifecycle of the parasite and can be source of infection for human Intermediate host: host in which a parasite develops to some extent but not to sexual maturity and transmits agent of disease passively 6
Terminologi in the Parasitology: Paratenic host: host in which a parasite survives without t undergoing further development Vektor: any agent, such as water, wind, or insect, that transmits a disease organism actively Symbiosis: interactions among organism in which one organisms lives with, in or on the body another 7
Terminologi in the Parasitology: Commensalisms: kind of symbiosis; can be benefits organism is neither harmed nor helped by association Mutualisms: type of symbiosis in which both host and symbiotic benefit from the association 8
Binomial Nomenclature Scientific system of naming plants and animals Genus: surname Species: first name Strain: second name Underlined or italic 9 Nurfida
Classification Phylum Class Class Order Order Order Order Family Family Family Family Family Family Genus Genus Genus Genus Genus Genus Genus Genus 10 Species
Helminthic Parasites Trophoblastic metazoa MulticellularM ll l Three germ layers (cuticle, subcuticle, muscular) Helminths of medical importance Phylum Platylhelminthes (flatworms) Phylum Nemathelminthes (roundworms) 11
Classes Platyhelminthes Cestoidea (segmented, tapeworms) Trematoda (unsegmented, flukes) Nemathelminthes e t es Nematoda (rounded) 12
Comparison of Nematodes, Trematodes and Cestodes Shape Nematodes Trematodes Cestodes Cylindrical, Leaf-like, Tape-like, unsegment unsegmented segmented Sexes separate not-separate notseparate Body cavity Alimentary canal present absent absent present present, incomplete present Hooklets absent absent Often present 13
Introduction to Nematode Structuret Life Cycle Habitat Mode of infection Egg or larva production Classification 14
Structure Body wall Cuticle, subcuticular layer and muscular layer. Nervous system Nerve trunk, nerve ring (around oesophagus) and sensory papillae (cuticle) Digestive system Buccal cavity, +/- teeth/cutting plate, oesophagus, intestine/midgut, rectum & anus 15
Life Cycle (cont.) Direct type Infective stage -> adult stage e.g Trichuris trichuria Indirect type Several developmental stages e.g Ascaris (ingestion), hookworm (skin penetration) & filariasis (per cutaneous) 16
Habitat of nematodes in hosts intestine somatic 17 Large intestine Small intestine Enterobius Ascaris Hookworms Trichuris Strongyloides Trichinella Capillaria lymphatic conjunctiva Loa loa subcutaneous body cavity Loa loa Onchocerca Dracunculus Mansonella spp.
Mode of infection ingestion Eggs in food, water Embryos in intermediate host Encysted embryos in meat Inhalation; ex: Acanthamoeba spp Insect bite Vectors: Aedes, Anopheles, Culex, Chrysops, Culicoides, Simulium Skin penetration by filariform larva 18
NEMATODE Lay eggs (oviparous) Hatch larvae (ii (viviparous)) Ascaris Trichuris Hookworms Enterobius Larva hatch out immediately from egg (ovo-viviparous) Wuchereria Brugia Dracunculus Trichinella Strongyloides stercoralis 19
Common conditions / terms related to nematodes Soil transmitted helminths hookworms filarial worms cutaneous larva migrans visceral larva migrans 20
Reference: Beaver, P.C., Jung, R.C. 1984. Clinical parasitology. 9 th ed. Phl Philadelphia, l h Lea & Febringer. p.15-17 Markel & Vogel. Medical parasitology 8th ed. p.269-297 Miyazaki, I. 1991. An illustrated book of helminthic zoonosis. Tokyo : International Medical Foundation of Japan, p. 1-5 Schimidt, G.D., Roberts, L.S. 2005. Foundation of parasitology. 7 th ed. Mc Graw Hill. p. 411-435 21