Question

Infective stage of Plasmodium is

• A. Trophozoite
• B. Merozoite
• C. Schizont
• D. Sporozoite

Answer 1

The correct option is D Sporozoite

The life cycle of Plasmodium that infect humans follows three stages: (I) infection of a human with sporozoites; (II) asexual reproduction and (III) sexual reproduction. The two first stages take place exclusively into the human body, while the third one starts in the human body and is completed into the mosquito organism. The human infection begins when an infected female anopheles mosquito bites a person and injects infected with sporozoites saliva into the blood circulation. That is, the first life stage of plasmodium (stage of infection). The next stage in malaria life cycle is the one of asexual reproduction that is divided into different phases: the pre- erythrocytic and the erythrocytic phase. Within only 30- 60 minutes after the parasites inoculation, sporozoites enter through blood circulation to their first target, the liver. The sporozoites enter the liver cells and start dividing leading to schizonts creation in 6- 7 days. Each schizont gives birth to thousands of merozoites (exoerythrocytic schizogony) that are then released into the blood stream marking the end of the exoerythrocytic phase of the asexual reproductive stage.

Therefore, the correct answer is option D.