Life Cycle of Malaria Plasmodium

• The many species of hepatic malaria plasmodium have a complex life cycle. While they have only two hosts, a human primary host and a mosquito secondary host, the pattern of reproduction and infection in the human body involves several clear and distinct stages and strategic goals. The simplest element of the life cycle is that found in the mosquito.
  
  

Malaria in Mosquitoes

• Malaria infects a mosquito when the female takes a blood meal from an infected human source. Along with the blood, the mosquito brings in male and female gametophyte cells. These cells have been specifically produced in the life cycle to be exported to a mosquito. Only in the mosquito will the two forms combine to form a new plasmodium by sexual reproduction. When the two have combined, a diploid ookinete is formed that will penetrate the gut of the mosquito and take up residence in the abdomen. Once in residence, the ookinete will form a cyst, within which will occur cell divisions producing a large number of asexual needle-like sporozoites. The sporozoites will work their way through the body of the mosquito toward the head and will settle in the salivary glands of the mosquito, ready to be injected back into a human host. So the pattern in the mosquito is male and female gametes combining to form diploid ookinetes, which enter the abdomen of the mosquito, turn into cysts and produce sporozoites, which line up in the salivary glands to go back to a human host: four basic units of the life cycle.
  
  

In The Human Liver

• When the sporozoites enter the human blood stream, they are carried around the body until they pass into the liver. In the liver, they penetrate liver cells and begin to transform into schizonts. A mature schizont is a cell that ruptures, releasing many new cells called merozoites. Merozoites are the primary invasive cell of the life cycle in the human. Merozoites invade more than other liver cells. They also enter the blood stream where they invade red blood cells.
  
  

In the Red Blood Cells

• Two different patterns of cell behavior can occur inside the red blood cells. The most common is for the merozoite to enlarge into a ring-shaped cell with a single nucleus, called a ring trophozoite. The nucleus of this cell will divide asexually and produce a multinucleated ring shaped cell, which will then begin to divide into more merozoites. In time, the red blood cell will burst, releasing merozoites and toxins into the blood stream. The toxins will cause the symptoms associated with malaria. The merozoites will find new red cells to invade, where they will either repeat the pattern, or begin the second pattern of the life cycle.
  
  In the second pattern, the ring trophozoite never forms. Instead, the merozoite metamorphoses into a male or female gametophyte. The gametophytes will travel in the blood waiting to be drawn into a feeding mosquito, where they will begin the mosquito portion of the life cycle.
  
  

Importance of Plasmodium Berghei

• Plasmodium berghei has been an important element in the attempts to learn how to manage and eradicate malaria. Because of the extreme similarity of life cycle and infectious behavior, the plasmodium makes an ideal model for treatments and for investigations into the more refined aspects of infection.
  
  Plasmodium berghei's genetic map has been completed, bringing hope that further understanding of all malarias will be possible, and that elements that cause berghei to be noninfectious to humans can be brought into play to deal with other malarias.