Malaria Graduation Card

The malaria-causing parasite, Plasmodium, has a complex two-host lifecycle. In both hosts, the parasite must use and migrate through multiple tissues in order to develop. Though it is known for its effects on humans, mosquitoes are the definitive host for Plasmodium because that is where the gametes meet.

When infected mosquitoes bite a human, Plasmodium sporozoites are introduced into the bloodstream. The sporozoites infect liver cells where they mature into schizonts. These rupture and release merozoites into the bloodstream, which invade the red blood cells to continue reproducing asexually. Some of these parasites will differentiate into gametocytes, waiting for an unsuspecting mosquito to feed. In the mosquito gut the gametocytes mature and fuse to form a zygote. The zygotes develop into ookinetes which invade the gut wall to continue developing into oocysts. These rupture, releasing sporozoites that migrate to the salivary glands waiting for the mosquito to feed again (1).

There are several main causative agents of malaria in humans, including Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale, and Plasmodium malariae (1). There are, however, strains of Plasmodium for many other animals including birds and monkeys that do not infect humans (2). For human varieties, Plasmodium is generally constrained to the geographical ranges of its mosquito hosts (from the Anopheles genus - there are many other types of mosquitos that do not carry Plasmodium) (1). These ranges are usually topical and subtropical areas and lower altitude regions (1).

1) https://www.cdc.gov/dpdx/malaria/index.html

2) 10.15212/zoonoses-2021-0015

Greeting Cards Team:

Dr. Chenhua Li (Lead, Ideas), Dr. Þórey Jónsdóttir (Illustrator, Ideas), Dr. Stephen Pollo (Writer, Researcher), Yuanzhe Wang (Digital Consultant).