The document summarizes the life cycle of Plasmodium, the parasite that causes malaria. It describes how a female Anopheles mosquito transmits sporozoites to humans, where they develop in the liver and blood cells. In the liver, sporozoites multiply and form merozoites, which then infect red blood cells. Inside red blood cells, the parasites develop through ring, trophozoite, and schizont stages, multiplying and forming more merozoites. Some merozoites develop into male and female gametocytes, which a mosquito can ingest and continue the life cycle. Relapses can occur if dormant liver stages called hypnozoites later develop into schizonts.
3. • The Parasite which cause malaria in man and otheranimals belong to
• Class:- Sporozoa
• Suborder – Hemosporidia
• Genus: Plasmodium
• Most common species found in man ate:
1. Plasmodium Vivax
2. Plasmodium Falciparum
3. Plasmodium Malariae
4. Plasmodium ovale
4. • In the life cycle of Plasmodium, a female Anopheles
mosquito (the definitive host)transmits a motile infective
form (called the sporozoite) to a vertebrate host such as a
human (the secondary host), thus acting as a transmission
vector.
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7. • Sporozoites from the saliva of a biting female mosquito are
transmitted to either the blood or the lymphatic system of the
recipient.
• Malaria also spreads through:
•Transfusion of malaria from the contaminated transfused blood.
•By sharing contaminated needle and syringes mostly in the drug
abusers.
•Congenital malaria which is rare.
8. ASEXUAL CYCLE OR SCHIZOGONY IN MAN
• It occus in human liver cell (liver schizogony) and in RBC
(erythrocytic schizogony).
• Asexual cycle or schizogony in human is completed in following
phases
1. Pre-erythrocytic schizogony
2. Exo-erythrocytic cycle
3. Erythrocytic cycle
4. Post-erythrocytic cycle
5. Formation of gametocytes
9. PRE-ERYTHROCYTIC CYCLE
• Sporozoites enters into parenchymatous
cell of liver.
• Sporozoites in liver cell grow in size and become spherical in shape
called schizonts.
• The nucleus of schizont multiply asexually (multiple fission) and
forms thousands of merozoites.
• These gives pressure to the wall of liver cell and merozoites are
liberated out.
• The process of formation of many merozoites from single
10. ERYTHROCYTIC CYCLE
• Single merozoite enters into single RBC and
passes through trophozoite stage, schizont
stage and merozoite stage
11. EARLY TROPHOZOITE
• This is a ring-like malarial parasite
following the invasion of RBCs.
• Giemsa stain shows it as blue stain
cytoplasmic circle connected to red chromatin dot.
• The space inside the ring is known as vacuole.
12. TROPHOZOITES
• The shape varies according to the
type of malarial parasite.There are a
cytoplasmic circle and the chromatin dot.
• More space is taken by the developing trophozoites.
• Pigments are brown in color.
13. IMMATURE SCHIZONT
• There is active chromatin replication.
Visible cytoplasmic material surrounds
the growing chromatin.
• Pigments are often brown.
• It occupies more space in the RBC.
15. POST-ERYTHROCYTIC CYCLE
• Sometimes, some merozoites produced after
erythrocytic cycle invade the liver cell and undergo
another schizogonic development in the liver cell.
This is called post-erythrocytic cycle.
16. FORMATION OF GAMETOCYTES
• After some generation of erythrocytic cycle, some of
the merozoites invade the new RBC. They grow in
size but do not develop into schizonts instead they
develop into gametocytes.
• The microgametocytes are smaller in size, cytoplasm
stains light blue and nucleus is large and diffuse.
• The macrogametocytes are larger, the cytoplasm
stains deep blue and the nucleus is small and
compact.
17. EXO-ERYTHROCYTIC SCHIZOGONY
• The exo erythroic cycle resembles the pre-erythrocytic cycle. Some
sporozoites, on entering into liver cells do not undergo asexual
multiplication but enter into a resting (dormant) phase.
• The resting stage of the parasite is krown as hypnozoite.
• After some period (usually up to 2 years) hypnozoites reactivate to
become schizonts and release merozoites.These merozoites attack
red blood cells and are responsible for relapse of malaria. Exo-
erythrocytic schizogony is absent in P.falciparum, therefore, relapses
do not occur in malaria caused by P. falciparum.
