2011apicomplexa - Phylum Apicomplexa Class Sporozoea...

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1 Phylum Apicomplexa • Class Sporozoea • Subclass Coccidia – Order Eucoccidia • Suborder Haemosporina – Genus Plasmodium • Suborder Eimeriina – Genera Toxoplasma, Cryptosporidium, Isospora • Subclass Piroplasmia • Genus Babesia General Characteristics • Morphology • Subpellicular microtubules • Distinctive organelles: Rhoptries, Micronemes Dense granules.
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2 Phylum Apicomplexa • Class Sporozoea • Subclass Coccidia – Order Eucoccidia • Suborder Haemosporina Genus Plasmodium • Suborder Eimeriina – Genera Toxoplasma, Cryptosporidium, Isospora • Subclass Piroplasmia • Genus Babesia • Four species infect humans. • All are transmitted by female Anopheles mosquitoes • Infect red blood cells Plasmodium falciparum (all RBC) – malignant tertian Plasmodium vivax (Retic) benign tertian Plasmodium ovale (Retic) benign tertian Plasmodium malariae (older RBC) quartan malaria Plasmodium knowlesi? – (24 hour blood stage cycle Genus Plasmodium
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3 Plasmodium falciparum - Epidemiology • Vector: Anopheles spp. – Anopheles gambiae complex, A. funestus, • Distribution. P. falciparum mostly in tropics • 300 to 500 million cases yearly with at least 2-3 million deaths. • Children and newly exposed • Selection for resistance genes A. albimanus evening and early morning feeder Parasite stages • Sporozoite - • Merozoite – free parasites released from infected cells • Ring stage – early trophozoite • Trophozoite • Schizont – Asexual division occurs here • gametocytes
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4 Plasmodium Life Cycle Life Cycle • Sporozoites migrate to liver – infect hepatocytes (exoerythrocytic stage) • Merozoites are released into blood • Infect red blood cells –erythrocytic stage • In blood cells develop as rings, trophozoites and schizonts (asexual reproduction – schizogony) • Blood cells rupture, merozoites released • Some parasites develop into gametocytes
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5 Life cycle cont’d • Mosquito takes up gametocytes with meal • Gametes exflagellate in mosquito gut • Gametes fuse and form zygotes (sexual reproduction) • Oocyte develops in gut wall of mosquito • Sporoblasts are formed that differentiate into sporozoites • Sporozoites migrate to salivary glands • Are deposited in host during blood meal Parasite stages • Sporozoite - • Merozoite – free parasites released from infected cells • Ring stage – early trophozoite • Trophozoite • Schizont – Asexual division occurs here • gametocytes
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6 Clinical Presentation • Initial fever episode 10 to 14 days after bite – Pre- patent period • Fevers occur every 36 to 72 hours thereafter • Characteristic presentation – chills (shaking), hot stage (104 o F body temperature, altered consciousness, abdominal pain, diarrhea); sweat stage (fatigue) • Massive red cell lysis results in anemia. • Multiple organ diseases: Parasites in brain cause
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2011apicomplexa - Phylum Apicomplexa Class Sporozoea...

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