OIA1010 PARASITOLOGY

Parasites

Parasite: organism bare food and shelter temporarily or permanently and living in or on another organism

Facultative: able live both free and parasite living (e.g., Strongyloides sp.)

Obligated: living permanently in host, cannot live w/o host (e.g., Trichomonos sp.)

Coprozix (spurious): foreign, pass through alimentally canal, found in feces.

Parasitism: organism depend another for living, one is living at the expsnes of the other and harmful (parasite) to the other organism (host).

Classification of Host

Definitive: harbor adults or final stages or sexual stage in parasite development (e.g., male)

Intermediate: larva stage or intermediate stage of development

(e.g., Taenia adult -> man, larva -> cattle)

Reservoir host (carrier): well adapted to parasites & tolerate infection but serve as source of infection

Relationship Between Organisms

Symbiosis: two different organisms living in close physical association, bring advantage of both

Mutualism: benefitting both organisms

Commensalism: one benefit while the other unaffected

Parasitism: one benefit while the other organism affected (harmful)

*Zoonosis: disease of animal but can be transmitted to man.

Classification of Parasites

Protozoa - microscopic, one-cell organism (facultative)

Entamoeba Histolytica (amoebiasis)

Cysts (formed stool) and trophozoites (diarrheal stool)

Transmission: ingestion of mature cysts in contaminated food, water or hands// exposure during sexual contact

Plasmodium sp. (malaria)

Transmission: female Anopheles mosquito with males not transmit disease (fed on plant juice)

Reproduction: sexually in mosquito; asexual in human (sporozoans -> produce merozoites -> trophozoits)

Life cycle: mosquito phase -> human phase -> gametocyte formation -> mosquito phase (continued)

Toxoplama Gondii - transmission through cats

Helminths - large multicellular organism (general visible to naked eye)

Nematodes (roundworm)

2 phases: lungs & intestinal

Ingestion and hatching of eggs in duodenum - larvae penetrate intestinal wall, enter blood vessels and embolise through liver to lungs - migrate to air spaces to trachea and swallowed into small intestine -> permanent residence

Cestodes (tapeworm)

Live in ileum

Transmission: Ingestion of raw or poorly cooked meat of infected cows

Larval form Lodge in skin, liver, muscles and CNS or any other organs

Adult has head, neck and body -> can up to 25 m, usually around 5 m length

Eggs present in feces -> infect organisms

Termatodes (fluke)

Acquired through contact of contaminated water due to urination or defecation by infected individual

Live in abdominal veins depend on species

Transmission: direct skin penetration but not contaminated food

2 types: intestinal & urinary tract Schistosomasis

Ectoparasites - broadly include blood-suckling arthropods (e.g., mosquito),

narrowly refer organism that attach or burrow into skin (e.g., ticks, fleas, lice and mites)

Bedbugs - feed solely on blood but does not transmit disease