Class Sporozoa

Class Sporozoa – No locomotory organs. All are parasites, cilia and flagella maybe present only in sex cells. No digestive organelles and contractile vacuoles. Has sexual and asexual reproduction.                                Asexual by sporogony and schizogony. Sexual by gamete formation.
8) Genus Plasmodium	Morphology: 4 types of plasmodium which causes different types of malaria. 1) P. Vivax - Benign tertian fever 2) P. Malaria - Quartan malaria 3) P. Falciparum – Sub tertian fever 4) P. Ovale – Mild tertian fever				Life Cycle: Transmission: Inoculative transference Female anopheles bites man àParasite goes into blood with its saliva àMinute sickle shaped sporozoite in the blood àAfter about half an hour the sporozoites enter liver cells and begin schizogony 1) Pre erythrocytic schizogony Sporozoites feed on glycogen àForm large and rounded schizonts àSchizont divides by multiple fission (schizogony) into 1000 small elongated merozoitesàThey attack RBC or liver cells. * If they attack liver cells then pre erythrocytic schizogony restarts. The time taken from sporozoite to reappear as merozoite into blood again is about 10 days (This is incubation period). 2) Erythrocytic schizogony Merozoite which attack RBC feed on amino acids of haemoglobin and becomes large and round in shape. àVacuole appears. Pushes its nucleus to one side (Called ring shaped trophozoite) àgrows and becomes amoeboid in shape and shows amoeboid movement (called amoeboid schizont) àEnlarges in size (mature schizont) àThe nucleus of schizont divides into 12-24 nuclei, each becomes erythrocytic merozoite. At center poisonous substance (haemozoin) accumulates. * Life cycle can continue for many generations. * After several generations of schizogony, some merozoites grow into large   cells inside erythrocytes. They form 2 types of cells – Gametocytes. Female gametocytes – Macrogametes with small excentric nucleus. Male gametes – Microgametes, clear cytoplasm with large nucleus. These gametes need cold blood. So goes into anopheles along with blood. Nucleus of microgamete divides 4-8 nucei. Flagellates form (exflagellation) The macrogametesà nucleus divides into 2 à one becomes polar body àbecomes mature macrogamete. Zygote elongates and becomes motile like a worm. This zygote is known as ookinete. àPenetrates the wall of the stomach and covered by outer stomach membrane and   this encysted zygote is called oocyst. à In oocyst, nucleus divides repeatedly to form many nuclei à Each nuclei forms a sporozoite (Sporogony). à Oocysts burst into sporozoite àGoes to saliva à cycle is completed when the anopheles bites another man.		Diagnosis: Smears of blood taken from the peripheral blood stream. Each day for 3-4 days should be checked for negative results before a patient is declared malaria free. * Indirect immunofluorescence. *  Indirect haemagglutination * Gel diffusion techniques				Disease: Malaria
9) Toxoplasma gondii	Morphology Merozoite stage It has sickled shaped of body. Front is narrow and back end is round and wide. Covered by pellicle. Large nucleus. Nutrition through microscopic openings in the pellicle. Reproduction same as plasmodium.				Life cycle: Reproductionsame as plasmodium. * Requires 2 hosts. Definitive host: Cat, sheep, pig Intermediate host: Human, some birds, mice Transmitted congenitally (through placenta) or by ingestion of cat feces contaminated food stuff. Oocysts containing sporozoites enter àRupture into sporozoites àSporozoites enter cells of mucosa àReproduction by binary fission takes place àCovered by cell membrane and forms pseudocysts. à   After destruction of infected cell, the sporozoites enter new cells à Under favourable conditions T. Gondii forms real cysts. When cysts get into body of definitive host, sporozoites when they enter the mucosa, they turn into round schizont, which begin to reproduce by schizogony. àMerozoites form à Affect new epithelial cells à After several generations, micro and macrogametes form àFertilization àZygote àForms oocyst à Inside oocyst sporogony takes place (4 sporozoites form) * Oocysts can be infective for both definitive and intermediate host.		Diagnosis: Same as plasmodium				Disease: Toxoplasmosis Can affect any organ of human body.