Symptoms of malaria in humans can vary depending on the severity of the infection and the species of the malaria parasite involved. Common symptoms include:
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Fever: Fever is often the first and most common symptom of malaria. It may be intermittent, with episodes of high fever followed by periods of normal temperature.
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Chills: Chills usually accompany the onset of fever and may be severe.
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Headache: Headaches are common and can range from mild to severe.
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Muscle and joint aches: Patients may experience generalized body aches, including muscle and joint pain.
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Fatigue: Malaria infection often leads to fatigue and weakness, which can be debilitating.
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Nausea and vomiting: Some individuals may experience nausea, vomiting, and loss of appetite.
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Sweating: Profuse sweating often follows episodes of fever, particularly during the fever's decline.
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Anemia: Severe malaria infections can lead to anemia due to the destruction of red blood cells by the malaria parasite.
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Jaundice: In cases of severe malaria, jaundice (yellowing of the skin and eyes) may occur due to liver dysfunction.
These symptoms are primarily caused by the life cycle of the malaria parasite (Plasmodium) within the human body. When an infected mosquito bites a human, it injects sporozoites into the bloodstream. The sporozoites travel to the liver, where they infect liver cells and multiply, causing liver damage. After maturing in the liver, the parasites are released into the bloodstream as merozoites, where they invade red blood cells.
Inside red blood cells, the parasites multiply further, eventually causing the cells to burst (lyse), releasing more parasites into the bloodstream. This cycle of invasion, multiplication, and lysis of red blood cells leads to the characteristic symptoms of malaria, including fever, chills, and anemia.
Additionally, the immune response to the malaria parasite can contribute to the symptoms. Inflammatory cytokines released by the immune system in response to the infection can cause fever, muscle aches, and fatigue. Severe malaria complications, such as cerebral malaria or organ dysfunction, can also contribute to the severity of symptoms.
