Plasmodium

Malaria is the common name for diseases caused by infection with single-celled parasites of the genus Plasmodium. They belong to the Apicomplexa. Organisms of this group are characterised by what is called an apical complex, a structural feature visible only under an electron microscope. The apical complex consists of a polar ring or rings, rhoptries (saccular organelles), micronemes (thread-shaped organelles), a conoid (cone-like structure) and subpellicular microtubules. Among the parasites of the genus Plasmodium four species have been identified which can cause disease in humans :

• Plasmodium falciparum

• Plasmodium vivax

• Plasmodium ovale

• Plasmodium malariae

Certain plasmodia (P. cynomolgi bastianelli, P. cynomolgi cynomolgi, P. brasilianum, P. schwetzi, P. inui, P. simium, P. knowlesi) which infect monkeys in the wild, may also infect humans, but because of the mild symptomatology and their rare occurrence they pose no problem in clinical practice. It is also possible that due to their rarity these zoonotic infections are missed in the normal clinical setting. Plasmodium ovale was discovered in 1922.

Category: Medicine Notes