About Plasmodium


Malaria is a disease caused by an infection of organisms from the genus Plasmodium. According to MedlinePlus, there are between 300 million and 500 million cases of malaria each year, of which 1 million will be fatal. Malaria most commonly occurs in the subtropics and tropics, as they are fertile breeding grounds for mosquitoes, which are responsible for infecting humans with this dangerous parasite.


MicrobiologyBytes explains that there are four different parasites that fall under the genus Plasmodium. They are Plasmodium ovale, vivax, malaria and falciparum. All four of these species can cause malaria in some form, but Plasmodium falciparum can cause the most severe disease. If not treated, it can lead to a condition known as cerebral malaria, which can be fatal.


The Plasmodium parasites develop and grow inside of mosquitoes. The female anopheline mosquito is responsible for transmitting the parasites to humans (as the males do not drink blood). MicrobiologyBytes explains that of the approximately 280 species of anopheline mosquito, only 60 are able to transmit Plasmodium parasites to humans. The parasite infects humans when an infected mosquito feeds on a human, which allows the Plasmodium organism to travel from the insect’s saliva to the human bloodstream.

Replication in Humans

In humans, the parasite first spreads to the liver via the bloodstream. Once in the liver, the parasite invades liver cells and multiplies. Between nine and 16 days later, the Plasmodium organism then returns to the bloodstream where it begins attacking and breaking down red blood cells. Plasmodium falciparum, according to MedlinePlus, invades red blood cells much more quickly and can be fatal within a few hours of symptoms appearing.

Symptoms and Diagnosis

The Mayo Clinic explains that some of the classic symptoms of malaria include moderate or severe chills and shaking as well as a high fever. Patients also sweat profusely and have a general feeling of malaise. Some patients also experience gastrointestinal symptoms, such as vomiting, nausea and diarrhea. The disease can also cause enlargement of the liver and spleen. Diagnosis typically occurs by examining blood smears for the parasite.


One commonly used medication for malaria is chloroquine. MedlinePlus notes that some strains of malaria are resistant to chloroquine, however, so alternate treatments are required. These can include qunidine or quinine combined with other antibiotics, such as tetracycline, clindamycin or doxycycline. Patients may also need intravenous fluids and help breathing for severe cases of malaria.

About this Author

Adam Cloe is an MD/PhD student at the University of Chicago. He has a Bachelor of Arts in biochemistry from Boston University, where he won an award for excellence in undergraduate science writing. He has been published in various scientific journals.