Plasmodium Dr. Shivani Gupta, PGGCG-11, Chandigarh

About Plasmodium -There are four types of Plasmodium which - Plasmodium, the parasite responsible for human malaria, is among the most researched genera of parasites in the world. -There are four types of Plasmodium which cause human malaria: Plasmodium falciparum, Plasmodium ovale, Plasmodium vivax, and Plasmodium malariae. -All of these are transmitted to human hosts solely by way of Anopheles mosquito vectors. -Cases of the disease are increasing in non- malarious countries as more people travel to Africa, India, Brazil, and some Asian nations, where the mosquito vectors are most prevalent. -Symptoms of the disease may go unnoticed or misdiagnosed; clinical signs include fever, chills, weakness, headache, vomiting, diarrhea, anemia, pulmonary and renal dysfunction, neurologic changes. Untreated malaria may result in death. Anopheles mosquito vector

Various species of Plasmodium

Morphology -While the four major species of Plasmodium differ in some ways from each other, they all share the same complex life cycle involving the insect (mosquito) vector and the human host. -When an infected Anopheles mosquito bites a human, sporozoites are injected with the saliva. The sporozoites are 10 -15 µm in length and about 1 µm in diameter. -They have a thin outer membrane, a double inner membrane below which lies the subpelicular microtubules. -They have 3 polar rings and the rhoptries are long, extending half the length of the body. The micronemes, convoluted elongate bodies, run forward to the anterior of the sporozoite entering a common duct with the rhoptries. Mitochondria are located at the posterior end. -After entering the circulatory system, the sporozoites make quick work of invading liver cells using the apical organelles -Inside the host's liver cell the Plasmodium cell undergoes asexual replication. The products of this replication, called merozoites, are released into the circulatory system.

Life Cycle

Structure of Plasmodium merozoite

Erythrocyte invasion by Plasmodium merozoite

Plasmodium vivax

Plasmodium ovale

Plasmodium malariae

Plasmodium falciparum