What Causes Malaria Disease?

Malaria is caused by a group of parasitic microorganisms called Plasmodium. These parasites are transmitted to humans through the bites of infected female Anopheles mosquitoes. There are several species of Plasmodium that can cause malaria in humans, with the most common ones being Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, and Plasmodium ovale.

Here’s how the transmission and infection process works:

  • Mosquito bite: When an infected female Anopheles mosquito bites a person, it injects the malaria parasites (in their sporozoite stage) into the person’s bloodstream along with its saliva.
  • Liver stage: The injected sporozoites travel to the liver, where they infect liver cells and multiply. During this stage, the person may not experience any symptoms.
  • Blood stage: After a period of development in the liver (known as the incubation period), the parasites are released back into the bloodstream in their merozoite form. They invade red blood cells and continue to multiply, causing the infected red blood cells to burst, releasing more merozoites.
  • Clinical symptoms: As the infected red blood cells rupture, the person experiences recurrent cycles of fever, chills, and flu-like symptoms. This is when clinical symptoms of malaria become evident.
  • Mosquito transmission: When a mosquito feeds on an infected person, it ingests the gametocytes (sexual forms of the parasite) present in the person’s blood. The gametocytes undergo sexual reproduction within the mosquito’s gut, resulting in the formation of new sporozoites.
  • Mosquito infection: The sporozoites migrate to the mosquito’s salivary glands, ready to be transmitted to another human during a subsequent mosquito bite.

Malaria can be a severe and life-threatening disease, particularly when caused by Plasmodium falciparum. The severity of the disease can vary depending on factors like the species of Plasmodium involved, the individual’s age, overall health, and access to medical care.

Prevention and control efforts against malaria include mosquito control measures (such as insecticide-treated bed nets and indoor residual spraying), antimalarial medications, and research towards the development of a malaria vaccine. Early diagnosis and prompt treatment are crucial in managing and reducing the impact of malaria on affected populations.