Life cycle of plasmodium

malaria life cycle

1. CLASSIFICATION & LIFE CYCLE OF PLASMODIUM

2. Plasmodium is  a parasitic protozoa Causes   malaria .   Plasmodium , which infects red blood cells in mammals (including humans), birds, and reptiles, occurs worldwide, especially in tropical and temperate zones. Plasmodium

3. Taxonomic classification Kingdom: Protista Subkingdom: Protozoa Phylum: Apicomplexa Class: Sporozoa . Order: Eucoccidiida . Family: Plasmodiidae Genus: Plasmodium

4. Species infecting human : P. vivax P. falciparum P. malariae   P. ovale  

5. Malaria

6. Plasmodium species Human infection Plasmodium vivax Benign tertian malaria Plasmodium falciparum Malignant tertian/pernicious malaria (most common and fatal) Plasmodium malariae Quartan malaria Plasmodium ovale Ovale tertian malaria Causative agents

7. Vector : The female Anopheles sp. Mosquito.

8. Plasmodium have two hosts: 1- A vertebrate host in which reproduction is asexual ( intermediate host ): Human 2- A blood-sucking insect, in which sexual reproduction takes place ( definitive host )- mosquito .

9. The infective stage(For Human) : sporozoites . - The infective stage for the mosquito is the gametocytes . In the intermediate host: Liver stage : 6 - 14 days. - Blood stage : 48 - 72 hrs. - Incubation period : 21 days.

10. Life cycle of Plasmodium Divided into 3 stages- Exoerythrocytic stage – in liver of man. Erythrocytic stage- in RBCs of man. Sporogonic stage- in mosquito (female Anopheles )

11. Exo-erythrocytic (hepatic) cycle Hypnozoites Sporozoites Salivary Gland LIFE CYCLE OF MALARIA Gametocytes Erythrocytic Cycle Zygote Oocyst Stomach Wall Pre-erythrocytic (hepatic) cycle sporozoites

12. Anopheles Transmission sporozoites injected with saliva enter circulation trapped by liver (receptor- ligand )

13. Exoerythrocytic Schizogony hepatocyte invasion asexual replication 6-15 days 1000-10,000 merozoites

14. Hyponozoite Forms some EE forms exhibit delayed replication (ie, dormant) merozoites produced months after initial infection only P. vivax and P. ovale relapse = hypnozoite recrudescence = subpatentt

15. Erythrocytic Stage intracellular parasite undergoes trophic phase young trophozoite called ‘ ring form ’ ingests host hemoglobin cytostome food vacuole hemozoin (malarial pigment)

16. Erythrocytic Schizogony N uclear division-begin schizont stage 6-40 nuclei budding merozoites erythrocyte rupture releases merozoites characterized by acute febrile attacks ( malaria paroxysms) Causes periodic episodes of fever alternating with symptom-free periods

17. paroxysms associated with synchrony of merozoite release between paroxysms temper- ature is normal and patient feels well falciparum may not exhibit classic paroxysms (continuous fever) Malaria Paroxysm tertian malaria quartan malaria

18. gametocytes erythrocytic schizogony 48 hr in Pf, Pv, Po 72 hr in Pm

19. Gametogenesis occurs in mosquito gut ‘ exflagellation ’ most obvious 8 microgametes formed

20. Sporogony occurs in mosquito (9-21 days) fusion of micro and macrogametes zygote  ookinete (~24 hr ) ookinete transverses gut epithelium ('trans-invasion '). ookinete  oocyst between epithelium and basal lamina asexual replication  sporozoites

21. sporozoites released. sporozoites migrate through hemocoel sporozoites 'invade' salivary glands. Stored in salivary glands of mosquito. Released into human body when mosquito bites another person.

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