Plasmodium

Plasmodium is a genus of protozoan that is best known for its infamous species that cause malaria. It was discovered by Charles Louis Alphonse Laveran while studying the parasites on a blood smear that he had withdrawn from a patient who had recently died from malaria. Then later on, the protozoan was researched by Ettore Marchiafava and Angelo Celli who were doing a long-term study for malaria. There are over 200 species of Plasmodium that are known to this world today; however, more and more species are being identified and studied. Out of all of these 200+ species, there are ten that actually affect and infect humans. The others that don't affect humans, affect animals such as birds, rodents, and reptiles. The four most common are P. falciparum, P. vivax, P. ovale, and P. malariae. These four are the best known because they are the malaria carrying parasites. 

Anatomy
Most species have 14 chromosomes, one mitochondrion, and a plastid. The appearance of these parasites are different from one another and also depend on what stage of their life cycle they are in. For P. falciparum, when it is in it's final stage (gametocyte), it has more of a sausage-looking shape or half-moon shape. It can have either chromatin in a single mass or a dark pigment mass. But in it's first stage, it has a very delicate and fragile cytoplasm. But when the P. falciparum is mature, it has around eight to twenty-four small merozoites and looks like it is clumped together into one big mass. P. vivax, in it's final stage, is more of a roundish or oval shape. It is either chromatin compact, eccentric, or a dispersed brown pigment. Then when it is mature, it is very large and has twelve to twenty-four merozoites. In P. ovale's final stage where it is a gametocyte, it has a roundish to oval shape that is compact. Just like P. vivax, it has a chromatin compact and carries a more diffused brown pigment. When it is mature, it is six to fourteen merozoites that have a large nuclei. Then lastly, for P. malariae, it is also roundish to oval and has a chromatin compact. It has a more scattered brown pigment, just like the other species. When it is mature, it has about six to twelve merozoites with big nuclei and also looks clumped together like a giant mass.  The two species, P. vivax and P. ovale are often so hard to decipher that it sometimes takes more than the help of technology to figure out which species they belong to. Although, normally today's tools are able to help distinguish their specific diagnosis. 

Reproduction


In order to understand the reproduction cycle, we must be able to understand the parasite in which plasmodium comes from, the mosquito. The life cycle begins with sexual reproduction in the host (female mosquito), and then asexual reproduction that occurs in the liver and red blood cells inside a human. When the plasmodium is trying to amplify itself in the blood cells, it creates repeated attacks of the disease on the body.  Plasmodium is spread when a mosquito interposes various sporozoites, that are found in the mosquito's saliva, into the human's bloodstream while it is supplying itself off a human. Then the sporozoites flow with the bloodstream and enter the liver. Then this is where the asexual reproduction takes place. The sporozoites multiply in the liver for an incubation period of seven to fourteen days. When the incubation period is finished, the sporozoites have produced around 10,000-30,000 daughter cells named merozoites. These invade and enter the red blood cells. Then in these red blood cells, the parasites multiply yet again through asexual reproduction to create eight to sixteen merozoites every forty-eight to seventy-two hours. Although this varies on the species of Plasmodium.  The infection causes the red blood cells to burst thus releasing and spreading all of the merozoites that were produced in that infected cell. After all of the merozoites are released, they then attack new red blood cells and then the entire cycle is repeated. Since there are toxic substances that are being released in all of the cells, when they burst, this causes more attacks of the actual disease and anemia as well. After these cycles have been repeated a few times, male and female gametocytes are created and then they commit sexual reproduction. While the mosquito is feeding off the human, they consume these gametocytes as well. This is where the entire Plasmodium life cycle is completed through sexual reproduction. It produces brand new sporozoites inside the saliva of the mosquito. Then this entire cycle as a whole is repeated. Some species like P. ovale and P. vivax can stay in the liver for a long period of time, for weeks, even years. The host won't have any idea until it comes out of the liver and attacks the bloodstream. 

Ecology
Plasmodium parasites are located all throughout the world. It demands warm climate and humid environments in order for it to replicate within the insect. Malaria, normally resides in areas only where the conditions allow the parasite to replicate and multiply itself. But more than often, malaria will be found confined in areas that are tropical or sub-tropical and altitudes that are below 1,500 m. The parasites that carry malaria are confined to tropical and sub-tropical areas of the world. The most dangerous parasite, P. falciparum is found mostly in widespread tropical areas. P. ovale is most predominant in Africa on the west coast region. P. malariae is mostly scattered around in different tropical areas and found also in Africa around the west coast region. Then the last malaria carrying species, P. vivax covers a lot of area, but is comparatively rare in other African countries. It is found in more cooler areas because it is more tolerant of lower temperatures. This is when P. vivax is more predominant than the others when transmission is seasonal. Although all of their different areas and locations vary. Normally, in warmer areas that are closer to the equator, P. falciparum spreads quickly and malaria is broadcasted year-round.

Malaria
Malaria comes from the protist Plasmodium. There are four species of Plasmodium that are able to produce malaria in different forms. These four are: Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale, and Plasmodium malaria. The most dangerous of the four is the P. falciparum because once infected and untreated, the result is fatal, causing cerebral malaria. Other results are: damage to the central nervous system, acute renal failure, severe anemia, and intense problems in the respiratory system. Malaria parasites are transported only through the female anopheline mosquito. The males are not able to carry the disease because their diet consists of only plant juices. In order to prevent malaria from spreading, people who travel or reside in disease-contaminated areas, need to be checked frequently.  The symptoms for malaria vary due to the different disease carrying parasites. Some symptoms of malaria are: periodic fever that transpires every 72 hours (for P. malariae.) For the other species, it would be fever occurring every 48 hours. These fever "attacks" produce sweating and rigidity. Some other symptoms are: chills, headache, fatigue, nausea, vomiting, dry (nonproductive) cough, muscle and/or back pain, and an enlarged spleen. Diarrhea, hypoglycemia, anemia, myalgias, and arthralgias are other clinical symptoms. The incubation period for the varies for all the species. For P. falciparum it takes nine to fourteen days for it to show. For P. vivax and P. ovale it takes twelve to eighteen days. Then for P. malariae it takes about eighteen to forty days for the symptoms of the disease to show. In some cases, symptoms can show up as fast as seven days, but for other cases it can take even eight to ten months for any of the symptoms to show. But normally this happens with just P. ovale and P. vivax. The incubation period can also be affected if someone has immunity from past infections or they are taking some sort of medicine to help prevent any infection. 
 * Symptoms