LIFE HISTORY OF PLASMODIUM

🦟 Life Cycle of Plasmodium

Two main phases: Asexual Cycle in Humans & Sexual Cycle in Mosquito

🅰️ Asexual Cycle of Plasmodium in Humans

1️⃣ Exoerythrocytic (Liver) Cycle

• 🦟 Sporozoites are injected into human blood by a female Anopheles mosquito.
• ⏱️ Within 30 minutes, they reach the liver and enter liver cells using enzymes.
• 🔬 They develop into cryptozoites and multiply into cryptomerozoites by schizogony.
• 💥 Liver cells burst, releasing cryptomerozoites into blood. Some enter RBCs.

2️⃣ Erythrocytic (RBC) Cycle

• 🔴 Merozoites in RBCs become ring-like trophozoites (signet-ring stage).
• 🍽️ Trophozoites feed on hemoglobin and form haemozoin pigment.
• 🧬 They grow, divide by mitosis, and form many merozoites.
• 💥 RBCs burst, releasing merozoites and causing malaria fever.
• ♻️ The cycle repeats, causing fever, chills, and RBC destruction.
• 🌟 Some merozoites become gametocytes (♂️ microgametocytes & ♀️ macrogametocytes).
• ⏰ Gametocytes appear at night and disappear in the morning.

🅱️ Sexual Cycle of Plasmodium in Mosquito

• 🦟 Mosquito sucks blood with gametocytes from infected human.
• 💨 All other RBC stages are digested; gametocytes survive in the mosquito’s stomach.

❤️ Fertilization

• ♂️ Microgametocyte produces 6–8 sperm-like microgametes by exflagellation.
• ♀️ Macrogametocyte becomes a macrogamete (ovum).
• 💕 One sperm enters ovum → forms a zygote.

🪱 Ookinete to Oocyst

• 🐛 Zygote becomes motile ookinete and penetrates stomach wall.
• 🔵 Becomes round, forms a cyst called oocyst.
• 🎈 Oocyst grows and forms thousands of sporozoites by sporogony.
• 💥 Oocyst bursts, sporozoites enter mosquito’s body (haemocoel).

✨ Final Step

• 🚀 Sporozoites reach salivary glands.
• 🦟 Ready to be injected into the next human host!

🔁 Alternation of Generations & Hosts

• 🧬 Asexual phase: Starts in mosquito, continues in human.
• ❤️ Sexual phase: Starts in human, completed in mosquito.
• 🧑‍🤝‍🧑 Alternation of generation: Switch between sexual & asexual stages.
• 🦟 Alternation of host: Switch between mosquito & human.

🖼️ Diagram: Life Cycle of Plasmodium