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SBM 2022 Medical Parasitology & Entomology

SBM 2022 Medical Parasitology & Entomology. Lecturer: Sr. Norazsida Ramli. Course assessment. Mid semester: 40 % Quiz/ assignment: 10% Final examination: 50%. What is Parasitology?.

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SBM 2022 Medical Parasitology & Entomology

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  1. SBM 2022Medical Parasitology &Entomology Lecturer: Sr. Norazsida Ramli

  2. Course assessment • Mid semester: 40 % • Quiz/ assignment: 10% • Final examination: 50%

  3. What is Parasitology? • Parasite: a live organism living in, or on , and having some metabolic dependence on another organism known as a host. • A weaker organism that obtains food and shelter from the association. • It may be a pathogen, causing disease in a host or it maybe nonpathogenic (causing no harm). • Host: the harboring species.

  4. THE NATURE OF HOST-PARASITE INTERACTIONS Symbiosis interaction– a permanent association of two organisms that cannot exist independently. • Mutualism – both organisms are benefited. • Comensalism – one partner is benefited, the other is unaffected. • Parasitism: any reciprocal association in which a species depends upon an other for its existence.

  5. Ectoparasite: parasite that lives on the outside of the host (infestation). -Example: tick, mite. • Endoparasite: parasite that lives within the body of the host (infection). -Example: Plasmodium sp.

  6. Facultative parasite: parasites that capable of leading both a free and a parasitic existence. For example, Halicephalobus (Micronema) deletrix , a saprophytic soil nematode that is found free-living in nature, has been reported to produce pathology in the CNS of horses. • Obligate parasite: parasites that take up a permanent residence in and are completely dependent upon the host. Example: Plasmodium sp.

  7. Incidental parasite: parasite that establishes itself in a host which it does not ordinarily live. For example, Parelaphostrongylus (Pneumostrongylus) tenuis normally is found in neurologic sites within the definitive host, white-tailed deer • Temporary parasite: is free living during part of its existence and seeks its host intermittently to obtain nourishment.

  8. Permanent parasite: remains on or in the body of the host from early life until maturity, sometimes for its entire life. • Pathogenic parasite: parasite that cause injury to the host by its mechanical, traumatic, or toxic activities. • Pseudoparasite: an artifact mistaken for a parasite. • Coprozoic parasite: a foreign species that has passed through the alimentary tract without infecting the host. • Zoonosis: a disease that caused by zoonotic infection. Can be transmitted from animal to human not from human to animal.

  9. Geographic distribution • Tropical countries are most favorable places for the survival, larval development, and transmission of parasites. • WHY?????? Bcoz……. • Optimal conditions of temperature and humidity are present.

  10. Short summer season (temperate zones) prevents the development of many species that required high temperatures during their larval stages. • Intense dry heat/direct sunlight may destroy the larval forms. • Low temperatures arrest the development of eggs and larvae and may even destroy them. • Freezing temperatures/snow force humanity to use privies and prevent general soil pollution.

  11. Moisture is essential for the development of free-living larvae and propagation of intermediate hosts. Example: arthropods, snails and fishes.

  12. Types of host • Definitive host • Intermediate host • Paratenic host • Incidental host • Dead-end host • Reservoir host

  13. Definitive host • The final host harbors the adult or sexual stage of the parasite. • Example: human for the Scistosome sp.

  14. Intermediate host (IH) • Host that part or all of the larval or asexual stage may take place in another animal. • Example: snail for the schistosome. • It can be, 2 intermediate hosts for a parasite life cycle: primary and secondary intermediate host. • Example: Diphyllobothrium latum, 10 IH is copepod, 20 is fish.

  15. Paratenic host • An animal that harbors the parasite in an arrested state of development; • However the parasite is capable of continuing its cycle in a subsequent suitable host. • Act as a transportation for parasite. • Example: Shrew (tupai tanah)

  16. Incidental host • Host that refer to the situation in which the infected individual is not necessary for the parasite’s survival or development. -example: the human being in the case of trichinosis.

  17. Dead-end host • Human or incidental host is called as dead-end host if the cycle for transmission of the parasite is such as that it cannot be transmitted further.

  18. Reservoir host • Animal that harbor the same parasite. • These hosts ensure continuity of the parasite’s life cycle and act as additional sources of human infection. • Example: The rabbit as new reservoirhost of enterohemorrhagic Escherichia coli.

  19. Life cycle • Directly –simple , only need a host. • Indirectly –complicated, need more than a host.

  20. Vector • Biological vector -act as transportation and host as well -example: mosquito • Mechanical vector -act as transportation only. -example: fly

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