Life Cycle of Plasmodium - Practice Questions & MCQ

• Plasmodium enters the human body as sporozoites (infectious form) through the bite of infected female Anopheles mosquito. 
• The parasites initially multiply within the liver cells and then attack the red blood cells (RBCs) resulting in their rupture. 
• The rupture of RBCs is associated with the release of a toxic substance, hemozoin, which is responsible for the chill and high fever recurring every three to four days.
• When a female Anopheles mosquito bites an infected person, these parasites enter the mosquito’s body and undergo further development. 
• The parasites multiply within them to form sporozoites that are stored in their salivary glands. When these mosquitoes bite a human, the sporozoites are introduced into his/ her body, thereby initiating the events mentioned above. 
• It is interesting to note that the malarial parasite requires two hosts – humans and mosquitoes – to complete its life cycle.
• The female Anopheles mosquito is the vector (transmitting agent) too.

Human Species of Plasmodium & Types of Malaria

Plasmodium vivax:

• It is most common in India.
• Its incubation period is about 14 days.
• It causes benign tertian malaria. 
• Recurrence of fever occurs after every 48 hours.

Plasmodium falciparum:

• It is responsible for severe infection in Africa and parts of tropics.
• Its incubation period is about 14 days.
• It causes malignant tertian malaria.

Plasmodium malariae:

• It is common in tropical Africa, Burma, Sri Lanka, and parts of India.
• It is the only species that can infect other primates as well.
• Recurrence of fever is after every 72 hours.
• It causes quartan malaria.

Plasmodium ovale:

• This is the rarest of four species.
• It is mostly found in tropical Africa.
• It causes mild tertian malaria.