Malaria is caused by a type of microscopic parasite that's transmitted most commonly by mosquito bites.

Mosquito transmission cycle

  • Uninfected mosquito. A mosquito becomes infected by feeding on a person who has malaria.
  • Transmission of parasite. If you're the next person this mosquito bites, it can transmit malaria parasites to you.
  • In the liver. The parasites then travel to your liver — where they can lie dormant for as long as a year.
  • Into the bloodstream. When the parasites mature, they leave the liver and infect your red blood cells. This is when people typically develop malaria symptoms.
  • On to the next person. If an uninfected mosquito bites you at this point in the cycle, it will become infected with your malaria parasites and can spread them to the next person it bites.

Other modes of transmission

Because the parasites that cause malaria affect red blood cells, people can also catch malaria from exposures to infected blood, including:

  • From mother to unborn child
  • Through blood transfusions
  • By sharing needles used to inject drugs
Jan. 25, 2013