Plasmodium in the context of "Plasmodium knowlesi"

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⭐ Core Definition: Plasmodium

Plasmodium is a genus of unicellular eukaryotes that are obligate parasites of vertebrates and insects. The life cycles of Plasmodium species involve development in a blood-feeding insect host which then injects parasites into a vertebrate host during a blood meal. Parasites grow within a vertebrate body tissue (often the liver) before entering the bloodstream to infect red blood cells. The ensuing destruction of host red blood cells can result in malaria. During this infection, some parasites are picked up by a blood-feeding insect (mosquitoes in majority cases), continuing the life cycle.

Plasmodium is a member of the phylum Apicomplexa, a large group of parasitic eukaryotes. Within Apicomplexa, Plasmodium is in the order Haemosporida and family Plasmodiidae. Over 200 species of Plasmodium have been described, many of which have been subdivided into 14 subgenera based on parasite morphology and host range. Evolutionary relationships among different Plasmodium species do not always follow taxonomic boundaries; some species that are morphologically similar or infect the same host turn out to be distantly related.

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👉 Plasmodium in the context of Plasmodium knowlesi

Plasmodium knowlesi is a parasite that causes malaria in humans and other primates. It is found throughout Southeast Asia, and is the most common cause of human malaria in Malaysia. Like other Plasmodium species, P. knowlesi has a life cycle that requires infection of both a mosquito and a warm-blooded host. While the natural warm-blooded hosts of P. knowlesi are likely various Old World monkeys, humans can be infected by P. knowlesi if they are fed upon by infected mosquitoes. P. knowlesi is a eukaryote in the phylum Apicomplexa, genus Plasmodium, and subgenus Plasmodium. It is most closely related to the human parasite Plasmodium vivax as well as other Plasmodium species that infect non-human primates.

Humans infected with P. knowlesi can develop uncomplicated or severe malaria similar to that caused by Plasmodium falciparum. Diagnosis of P. knowlesi infection is challenging as P. knowlesi very closely resembles other species that infect humans. Treatment is similar to other types of malaria, with chloroquine or artemisinin combination therapy typically recommended. P. knowlesi malaria is an emerging disease previously thought to be rare in humans, but increasingly recognized as a major health burden in Southeast Asia.

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Plasmodium in the context of Malaria

Malaria is a mosquito-borne infectious disease that affects vertebrates and Anopheles mosquitoes. Human malaria causes symptoms that typically include fever, fatigue, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. Symptoms usually begin 10 to 15 days after being bitten by an infected Anopheles mosquito. If not properly treated, people may have recurrences of the disease months later. In those who have recently survived an infection, reinfection usually causes milder symptoms. This partial resistance disappears over months to years if the person has no continuing exposure to malaria. The mosquitoes themselves are harmed by malaria, causing reduced lifespans in those infected by it.

Malaria is caused by single-celled eukaryotes of the genus Plasmodium. In mammals, it is spread through bites of infected female Anopheles mosquitoes. The mosquito bite introduces the parasites from the mosquito's saliva into the blood. The parasites travel to the liver, where they mature and reproduce. Five species of Plasmodium commonly infect humans. The three species associated with more severe cases are P. falciparum (which is responsible for the vast majority of malaria deaths), P. vivax, and P. knowlesi (a simian malaria that spills over into thousands of people a year). P. ovale and P. malariae generally cause a milder form of malaria. Malaria is typically diagnosed by the microscopic examination of blood using blood films, or with antigen-based rapid diagnostic tests. Methods that use the polymerase chain reaction to detect the parasite's DNA have been developed, but they are not widely used in areas where malaria is common, due to their cost and complexity.

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Plasmodium in the context of Anopheles

Anopheles (/əˈnɒfɪlz/) is a genus of mosquito first described by the German entomologist J. W. Meigen in 1818, and are known as nail mosquitoes and marsh mosquitoes. Many such mosquitoes are vectors of the parasite Plasmodium, a genus of protozoans that cause malaria in birds, reptiles, and mammals, including humans. The Anopheles gambiae mosquito is the best-known species of marsh mosquito that transmits the Plasmodium falciparum, which is a malarial parasite deadly to human beings; no other mosquito genus is a vector of human malaria.

The genus Anopheles diverged from other mosquitoes approximately 100 million years ago (mya), and, like other mosquitoes, the eggs, larvae, and pupae are aquatic. The Anopheles larva has no respiratory siphon through which to breathe, so it breathes and feeds with its body horizontal to the surface of the water. The adult mosquito hatches from the surface and feeds on the nectar of flowers; the female mosquito also feeds on blood, which animal diet allows them to carry and transmit parasites between hosts. The adult's feeding position is head-down, unlike the horizontal stance of the culicines. Anopheles are distributed almost worldwide, throughout the tropics, the subtropics, and the temperate regions of planet Earth. In hot weather, adult Anopheles aestivate, which is a state of dormancy that enables the mosquito to survive in hot dry regions, such as the Sahel.

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Plasmodium in the context of Chromista

Chromista is a proposed but controversial biological kingdom, refined from the Chromalveolata, consisting of single-celled and multicellular eukaryotic species that share similar features in their photosynthetic organelles (plastids). It includes all eukaryotes whose plastids contain chlorophyll c and are surrounded by four membranes. If the ancestor already possessed chloroplasts derived by endosymbiosis from red algae, all non-photosynthetic Chromista have secondarily lost the ability to photosynthesise. Its members might have arisen independently as separate evolutionary groups from the last eukaryotic common ancestor.

Chromista as a taxon was created by the British biologist Thomas Cavalier-Smith in 1981 to distinguish the stramenopiles, haptophytes, and cryptophytes. According to Cavalier-Smith, the kingdom originally consisted mostly of photosynthetic eukaryotes (algae), but he later brought many heterotrophs (protozoa) into the proposed group. As of 2022, the kingdom was nearly as diverse as the kingdoms Plantae and Animalia, consisting of nine phyla. Notable members include marine algae, potato blight, dinoflagellates, Paramecium, the brain parasite Toxoplasma, and the malarial parasite Plasmodium.

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Plasmodium in the context of Artemisinin

Artemisinin (/ˌɑːrtɪˈmsɪnɪn/) and its semisynthetic derivatives are a group of drugs used in the treatment of malaria due to Plasmodium falciparum. It was discovered in 1972 by Tu Youyou, who shared the 2015 Nobel Prize in Physiology or Medicine for her discovery. Artemisinin-based combination therapies (ACTs) have become standard treatment worldwide for P. falciparum malaria as well as malaria due to other species of Plasmodium. Artemisinin can be extracted from the herb Artemisia annua (sweet wormwood), which is used in traditional Chinese medicine. Alternatively, it can be prepared by a semi-synthetic method from a precursor compound that can be produced using a genetically engineered yeast, which is much more efficient than extraction from the plant.

Artemisinin and its derivatives are all sesquiterpene lactones containing an unusual peroxide bridge. This endoperoxide 1,2,4-trioxane ring is responsible for their antimalarial properties. Few other natural compounds with such a peroxide bridge are known.

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Plasmodium in the context of Plasmodium falciparum

Plasmodium falciparum is a unicellular protozoan parasite of humans and is the deadliest species of Plasmodium that causes malaria in humans. The parasite is transmitted through the bite of a female Anopheles mosquito and causes the disease's most dangerous form, falciparum malaria. P. falciparum is therefore regarded as the deadliest parasite in humans. It is also associated with the development of blood cancer (Burkitt's lymphoma) and is classified as a Group 2A (probable) carcinogen.

The species originated from the malarial parasite Laverania found in gorillas, around 10,000 years ago. Alphonse Laveran was the first to identify the parasite in 1880, and named it Oscillaria malariae. Ronald Ross discovered its transmission by mosquito in 1897. Giovanni Battista Grassi elucidated the complete transmission from a female anopheline mosquito to humans in 1898. In 1897, William H. Welch created the name Plasmodium falciparum, which ICZN formally adopted in 1954. P. falciparum assumes several different forms during its life cycle. The human-infective stage are sporozoites from the salivary gland of a mosquito. The sporozoites grow and multiply in the liver to become merozoites. These merozoites invade the erythrocytes (red blood cells) to form trophozoites, schizonts and gametocytes, during which the symptoms of malaria are produced. In the mosquito, the gametocytes undergo sexual reproduction to a zygote, which turns into ookinete. Ookinete forms oocytes from which sporozoites are formed.

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Plasmodium in the context of Plasmodium ovale

Plasmodium ovale is a species of parasitic protozoon that causes tertian malaria in humans. It is one of several species of Plasmodium parasites that infect humans, including Plasmodium falciparum and Plasmodium vivax which are responsible for most cases of malaria in the world. P. ovale is rare compared to these two parasites, and substantially less dangerous than P. falciparum.

P. ovale has recently been shown by genetic methods to consist of two species, the "classic" P. ovalecurtisi and the "variant" P. ovalewallikeri (split by Sutherland et al. 2010, names amended to binomials by Snounou et al. 2024). Depending on the type locality of the original P. ovale defined by Stephens, one of the proposed species (likely P. ovalecurtisi) may end up as a junior synonym of the old name. There is a statistically significant difference between the clinical parameters found in patients infected with either kind.

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Plasmodium in the context of Plasmodium species infecting birds

Species in six subgenera of Plasmodium infect birds - Bennettinia, Giovannolaia, Haemamoeba, Huffia, Novyella and Papernaia. Giovannolaia appears to be a polyphytic group and may be subdivided in the future.

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Plasmodium in the context of Plasmodium species infecting reptiles

Over 90 species and subspecies of Plasmodium infect lizards. They have been reported from over 3200 species of lizard but only 29 species of snake. Three species - P. pessoai, P. tomodoni and P. wenyoni - infect snakes. These species belong to the subgenera Asiamoeba, Carinamoeba, Fallisia, Garnia, Lacertamoeba, Ophidiella, Paraplasmodium and Sauramoeba. Additional species continue to be described.

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