Malign Malaria

What am I looking at?

This is a colored scanning electron microscopy image of a human red blood cell infected with the parasite that causes malaria. The infected cell is blue (1), and the uninfected cells around it are red (2).

Click on the right arrow to see another image (this one not in color) of a cell infected with plasmodium.

Biology in the background

Malaria is a severe illness that is transmitted to humans by the bite of an infected mosquito. Globally, it affects 290 million people each year and kills more than 608,000. Malaria infections are concentrated in warmer regions where Anopheles mosquitos thrive; nearly 95% of malaria infections are found in Africa.

Malaria is caused by a blood parasite called plasmodium, which has a life cycle that requires multiple hosts to grow and spread. The sexual reproduction stage of plasmodium happens in the intestine of a female mosquito, where the plasmodium gametocytes merge to form sporozoites, which are infectious to humans. The sporozoites escape from the mosquito’s intestine and move to its salivary glands, where they can be transferred into a human’s bloodstream through a bite. Once inside a human, the sporozoites reproduce asexually – basically making copies of themselves – inside liver cells and red blood cells. This is also where they transform into gametocytes again, ready to be transferred back to the next mosquito that bites an infected person.

A human red blood cell is about 8 micrometers across, or roughly 10 times smaller than the width of a human hair. At the stage in their life cycle when they are infecting a human, a plasmodium parasite can reach about the same length as the diameter of a red blood cell – from 7 micrometers to 9 micrometers.

Technique

These images were created using scanning electron microscopy.