Where can sporozoites of the malarial parasite be found?

Saliva of an infected female Anopheles mosquito

 The answer is (d) Saliva of an infected female Anopheles mosquito.

Sporozoites are the infective form of the malarial parasite. They are found in the salivary glands of female Anopheles mosquitoes. When the mosquito bites a human, the sporozoites are injected into the bloodstream. The sporozoites then travel to the liver, where they mature and reproduce. The mature parasites then infect red blood cells, where they continue to reproduce. This cycle of infection can cause malaria, a serious and potentially fatal disease.

The malarial cycle, also known as the malaria life cycle, refers to the series of events that occur during the transmission and development of the malaria parasite within humans and mosquitoes. There are several stages in the malarial cycle, involving different forms of the parasite and different hosts. Here is an overview of the malarial cycle:

1. Transmission to humans: The cycle begins when an infected female Anopheles mosquito bites a human and injects sporozoites, which are the infective form of the malaria parasite, into the person's bloodstream.
2. Liver stage: The sporozoites travel to the liver, where they invade liver cells and develop into a different form of the parasite called merozoites. During this stage, the infected person does not experience any symptoms.
3. Blood stage: The merozoites are released from the liver cells and invade red blood cells (RBCs). Inside the RBCs, the merozoites multiply rapidly and eventually rupture the RBCs, releasing more merozoites into the bloodstream. This causes the characteristic symptoms of malaria, including fever, chills, and flu-like symptoms.
4. Gametocyte formation: Some of the merozoites differentiate into sexual forms of the parasite called male and female gametocytes. These gametocytes can be taken up by another mosquito during a blood meal.
5. Transmission to mosquitoes: When a mosquito feeds on an infected human, it ingests the gametocytes along with the blood. Inside the mosquito's gut, the male and female gametocytes undergo sexual reproduction, forming a zygote.
6. Mosquito stage: The zygote develops into a motile form called ookinete, which penetrates the mosquito's gut wall and forms an oocyst. Inside the oocyst, the parasites multiply and develop into sporozoites.
7. Salivary gland stage: The mature sporozoites migrate from the oocyst to the mosquito's salivary glands. When the infected mosquito bites another human, it injects these sporozoites into the person's bloodstream, starting the cycle anew.

The malarial cycle continues as long as there are infected mosquitoes and susceptible humans in an area. Effective control measures aim to interrupt this cycle by targeting either the mosquitoes or the