Plasmodium is a single-celled, parasitic vesicle worm. Organisms of this genus are commonly referred to as Plasmodium parasites. There are five species of malaria parasites in this genus that infect humans with malaria, including Plasmodium falciparum, Plasmodium malariae, Plasmodium ovale, plasmodium vivax, and Plasmodium knowlesi. Other species of plasmodium infect other species of animals, including other primates, rodents, birds and reptiles.
History of discovery
The discoverer of the malaria parasite was the Frenchman Charles Louis Alphonse Laveran. In 1880, when he was working as a surgeon in Algeria, he noticed the presence of a microorganism in the red blood cells of malaria patients, and he was convinced that this microorganism (the malaria parasite) was the causative agent of malaria; it was the first time that protozoa were found to cause disease in humans. He was awarded the 1907 Nobel Prize in Physiology or Medicine for his discoveries and other studies on protozoa pathogenesis.
British physician Sir Ronald Ross (1857-1932), discovered the parasite parasitizing malaria parasite in the stomach of a malaria mosquito in 1897 while serving as a British military doctor in India. For discovering the vector of infection of the malaria parasite, he was awarded the 1902 Nobel Prize in Physiology or Medicine. The only person who discovered the mosquito that could transmit the malaria parasite was the Italian zoologist Giovanni Battista Grassi.
Basics
The basic structure of the parasite is the same as that of ordinary protists, which are the nucleus, cytoplasm and cell membrane. The later phases of the ring (trophozoite, the first stage of the main developmental phase) also contain malarial pigment, the product of the malaria parasite's digestion and decomposition of hemoglobin.
After staining with Giemsa's Stain or Wright's stain, the nucleus is purple-red, the cytoplasm is dark blue, and the malaria pigment is brown or black-brown. This is also one of the methods used in blood tests to detect the malaria parasite. When parasites parasitize red blood cells, they cause red blood cells to deform. Different species of plasmodium cause red blood cells to take on different shapes (and one of the important ways to identify malaria parasite species):
Red blood cells parasitized by Plasmodium vivax become larger and lighter in color, with tiny red dots appearing later.)
Red blood cells parasitized by Plasmodium ovate become larger and lighter in color, with distinctly thick red Shex points
Red blood cells parasitized by Plasmodium falciparum have thick purple-brown Maurer's dots
Red blood cells parasitized by The Three-Day Malaria Parasite have tiny red Ziemann's dots
life history
The life history of plasmodium is very complex. The life history of each class is basically the same, requiring both humans and malaria mosquitoes to host. In general, malaria parasites perform asexual reproduction in humans; sexual reproduction in mosquitoes.
Development in the human body
Two periods must pass, the extraterrestrial phase of red blood cells that develops in hepatocytes and the extrakinesis of red blood cells that develops within red blood cells.
Three types in the human body
Trophozoite (or active body, nutrient body)
After the parasite enters the form of red blood cells, the main purpose is to grow and feed. Trophozoite parasites feed on hemoglobin; they digest hemoglobin in plasmepsin enzymes. The trophozoite early cell nucleus is small, the cytoplasm is small, and the insect body is mostly ring-shaped, so it is also called "ring form". Then, as the body grows, the nucleus enlarges, the cytoplasm increases, and sometimes pseudopods protrude, and malaria pigments begin to appear in the cells.
Schizont
After the trophozoite matures, the nucleus of the malaria parasite begins to divide continuously. This stage is called a fission. At the end of the division, the cytoplasm also divides, and each nucleus forms a separate small cell called a merozoite.
Gametocyte
After the malaria parasite passes through several phases of mysosomes, a portion of the merozoites invade the red blood cells to develop. Their nuclei no longer divide, but enlarge; the cytoplasm increases, and the steps extend out of the pseudopod. Eventually it will develop into a gametophyte. Gametosites range in shape from round to crescent-shaped, and are male and female. The female is larger and the male is smaller.
Red blood cell extraphase
The exo-erythrocytic cycle, or infrared for short, refers to the stage before the parasite enters the red blood cell
The mature spores (sporozoite, or spores) of the malaria parasite enter the body's blood circulation with the bite of the female malaria mosquito
Enter the liver cells within about 30 minutes, begin asexual reproduction, and take up nutrient development within the liver cells
Plasmodium ovale and Plasmodium vivax produce dormant parasites called hypnozoites, or dormant seeds, which are reactivated after a period of time. This is thought to be associated with recurrence of ovate and vivax malaria [1].
The parasite continues to divide and reproduce, and finally produces infrared phase fissures
Infected liver cells rupture, and the myrosomes release myozoites
The intracytolic phase of red blood
Erythrocytic cycle, or red intracytic cycle for short, refers to the stage in which the malaria parasite has entered the stage of red blood cells
After the infected liver cells rupture, the mesozoites enter the bloodstream
Invades red blood cells, forms trophozoites, feeds and absorbs nutrients, grows and develops, and begins to divide and reproduce
It constantly divides and reproduces, forming a schizont in the red inner stage
Infected red blood cells rupture, releasing mesophiles
The previous steps are repeated continuously, and finally some of the fissures develop into hermaphrodites
Development in the body of the mosquito
By sucking the blood of the patient or carrier, the mosquito allows various types of protozoa in the blood to enter the mosquito; but only the gamete will continue to develop
In the stomach of mosquitoes, female and male gametophytes develop into female and male gametes
Smaller male gametes burrow into larger female gametes to form zygotes
Zygotes continue to elongate and are dynamic, called ookinetes.
The actuated zygotes eventually penetrate the stomach wall, forming a spherical oocyst under the elastic fibrous membrane of the stomach
Spores multiply (asexual) in the oocyst, then rupture, releasing the spores of the malaria mosquito
Plasmodium Falciparum's ring
Schizotron of Plasmodium Falciparum
Gamete of Plasmodium Falciparum