Explanation: Malaria is a parasitic disease caused by Plasmodium species, which are transmitted to humans through the bite of infected Anopheles mosquitoes. The life cycle of the Plasmodium parasite involves two main stages: the liver stage and the blood stage.
1. **Liver Stage**: When a person is bitten by an infected mosquito, the Plasmodium parasites are introduced into the bloodstream. They travel to the liver, where they invade liver cells (hepatocytes) and multiply. This stage is asymptomatic and lasts for about 5-16 days, depending on the species of Plasmodium.
2. **Blood Stage**: After multiplying in the liver, the parasites (now called merozoites) are released into the bloodstream, where they invade red blood cells (RBCs). Inside the RBCs, the merozoites multiply and cause the RBCs to rupture, releasing more merozoites that can infect other RBCs. This cycle of invasion, multiplication, and rupture of RBCs is what causes the symptoms of malaria, such as fever, chills, and anemia.
The primary cells affected by malaria are the red blood cells. The destruction of RBCs leads to anemia, which is a common symptom of malaria. Additionally, the rupture of RBCs releases toxins that can cause fever and other symptoms. While the liver is involved in the early stages of the infection, the symptoms of malaria are primarily due to the destruction of RBCs.
It is important to note that while brain cells are not directly affected by the Plasmodium parasite, severe cases of malaria can lead to cerebral malaria, a complication where infected RBCs block blood vessels in the brain, leading to neurological symptoms. However, the primary cells affected by the malaria parasite are the red blood cells.
In summary, the correct answer is (B) Red blood cells, as they are the primary cells impacted by and causing symptoms of malaria. The liver cells and brain cells are involved in the disease process but are not the primary cells affected by the Plasmodium parasite.