MP Board · Class 12 · Biology · Human Health and DiseasesDescribe the life cycle of Plasmodium in the human body and female Anopheles mosquito with a detailed step-by-step breakdown. Also, mention the main symptoms, causative agent, and prevention measures of malaria.

Causative Agent\nMalaria is caused by a protozoan parasite called Plasmodium (P. vivax, P. falciparum, and P. malariae). P. falciparum causes the most severe and fatal malignant malaria.

Life Cycle of Plasmodium

Plasmodium requires two hosts to complete its life cycle: human (secondary host) and female Anopheles mosquito (primary host/vector).

1. In Human Body (Asexual Cycle):

• Infection Entry: The infected female Anopheles mosquito bites a human and injects the parasite in the form of sporozoites along with its saliva.
• Liver Phase: Sporozoites reach the liver through blood circulation and reproduce asexually inside liver cells, causing them to burst.
• Erythrocytic Phase: Parasites released from liver cells attack Red Blood Cells (RBCs) and reproduce asexually, causing RBCs to rupture.
• Release of Hemozoin: Rupture of RBCs releases a toxic substance called hemozoin, which is responsible for recurring high fever and chills every 3 to 4 days.
• Gametocyte Formation: Parasites eventually differentiate into sexual forms called gametocytes (male and female) within RBCs.

2. In Mosquito (Sexual Cycle):

• Ingestion: When a female Anopheles mosquito bites an infected person, it ingests male and female gametocytes along with blood.
• Fertilization: Fertilization and development occur inside the mosquito's gut.
• Sporozoite Formation: The zygote develops into a motile ookinete, matures into an oocyst, and produces thousands of sporozoites.
• Salivary Gland Migration: Sporozoites migrate to the mosquito's salivary glands, making the mosquito ready to infect a new host.

Symptoms of Malaria

• High fever recurring periodically with shivering and chills.
• Profuse sweating as temperature drops.
• Nausea, vomiting, severe headache, and muscle pain.
• Anemia due to destruction of RBCs.

Prevention and Control

• Vector Control: Spraying insecticides like DDT and using biological control such as introducing Gambusia fish in ponds to feed on mosquito larvae.
• Personal Protection: Using mosquito nets, repellents, and wearing long-sleeved clothes.
• Hygiene: Avoiding stagnation of water in surroundings to prevent mosquito breeding.