Plasmodium species
are transmitted to humans by mosquitos.
Human infection from Plasmodium species causes malaria. The organism is transmitted between individuals via the Anopheles mosquito. According to "Sherris Medical Microbiology," approximately 2 billion people live in malaria endemic areas, with 25 to 50 percent of them carrying the plasmodium parasite at any given moment. Malaria kills one to three million people annually, the majority of them being children.
Definition of Plasmodium
Plasmodium is the genus name for the organisms that cause the disease malaria. These organisms are known for their intracellular life cycle. The parasite must enter the host cell to survive and, after inside, modify the host cell. There are four Plasmodium species that infect humans: P. vivax, P. ovale, P. malariae, and P. falciparum.
Plasmodium Life Cycle in Mosquito
The Plasmodium sexual cycle begins when a female mosquito of the genus Anopheles ingests circulating immature reproductive cells of male and female Plasmodium while feeding on a malaria infected human. In the gut of the mosquito, the cells mature and are fertilized, becoming a zygote. The zygote lodges in the gut wall of the mosquito and forms an enlarging cyst. The cyst eventually ruptures and releases the contents into the mosquito's body cavity, some of the cells get into the the salivary glands of the mosquito and make the mosquito infectious to the next human it bites.
Plasmodium Life Cycle in Human
The asexual portion of the Plasmodium life cycle takes place inside humans. The organisms enter the capillaries in the fatty layer of the human skin after a bite by the Anopheles mosquito. The organisms attach to and invade the liver within one hour. The organisms multiply within the liver cells and cause the liver cells to burst within one to two weeks, releasing more organisms into the circulation.
The Plasmodium organisms then invade human red blood cells and multiply. The red blood cells burst within 48 to 72 hours of invasion. Some Plasmodium organisms enter the sexual phase and are ingested by a feeding mosquito, restarting the cycle.
Physical Manifestations Infection
Plasmodium infection causes the clinical picture of malaria in humans. The infection is characterized by cyclical fevers and anemia. Generally the individual has a history of habitation of travel to endemic areas such as Africa, South America, or Southeast Asia.
Tags: Plasmodium species, Anopheles mosquito, blood cells, burst within, cells burst, cells burst within