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A plasmodium is also the macroscopic form of the protist
Protist

Protists ; eukaryote microorganisms. Historically, protists were treated as the kingdom Protista but this group is no longer recognized in modern taxonomy....
 known as a slime mold.


Plasmodium is a genus of parasitic protozoa
Protozoa

Protozoan are microorganisms classified as unicellular eukaryotes. While there is no exact definition of the term "protozoan", most scientists use the word to refer to a unicellular heterotrophic protist, such as an amoeba or a ciliate....
. Infection with these parasites is known as malaria
Malaria

Malaria is a Vector -borne infectious disease caused by protozoan parasites. It is widespread in Tropics and subtropical regions, including parts of the Americas, Asia, and Africa....
. The genus
Genus

A genus is a low-level taxonomic rank used in the classification of living and fossil organisms. The taxonomic ranks are domain , kingdom , phylum, class , order , family , genus, and species....
 Plasmodium was created in 1885 by Marchiafava and Celli
Angelo Celli

Angelo Celli was an Italy physician and Zoology who studied malaria.Celli graduated in medicine in 1878 at the Sapienza University of Rome, where he became Public health professor....
. Currently over 200 species in this genus are recognized and new species continue to be described.

Of the 200+ known species of Plasmodium, at least 10 species infect humans.






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A plasmodium is also the macroscopic form of the protist
Protist

Protists ; eukaryote microorganisms. Historically, protists were treated as the kingdom Protista but this group is no longer recognized in modern taxonomy....
 known as a slime mold.


Plasmodium is a genus of parasitic protozoa
Protozoa

Protozoan are microorganisms classified as unicellular eukaryotes. While there is no exact definition of the term "protozoan", most scientists use the word to refer to a unicellular heterotrophic protist, such as an amoeba or a ciliate....
. Infection with these parasites is known as malaria
Malaria

Malaria is a Vector -borne infectious disease caused by protozoan parasites. It is widespread in Tropics and subtropical regions, including parts of the Americas, Asia, and Africa....
. The genus
Genus

A genus is a low-level taxonomic rank used in the classification of living and fossil organisms. The taxonomic ranks are domain , kingdom , phylum, class , order , family , genus, and species....
 Plasmodium was created in 1885 by Marchiafava and Celli
Angelo Celli

Angelo Celli was an Italy physician and Zoology who studied malaria.Celli graduated in medicine in 1878 at the Sapienza University of Rome, where he became Public health professor....
. Currently over 200 species in this genus are recognized and new species continue to be described.

Of the 200+ known species of Plasmodium, at least 10 species infect humans. Other species infect animals, including bird
Bird

Birds are wing, Bipedalismal, endothermic , vertebrate animals that lay egg . There are around 10,000 living species, making them the most numerous tetrapod vertebrates....
s, reptile
Reptile

Reptiles, or members of the class Reptilia, are air-breathing, cold-blooded vertebrates that have skin covered in scale as opposed to hair or feathers....
s and rodent
Rodent

Rodentia is an Order of mammals also known as rodents, characterised by two continuously growing Incisors#The_Rodent_incisor in the upper and lower jaws which must be kept short by gnawing....
s. The parasite always has two hosts in its life cycle
Biological life cycle

A life cycle is a period involving one generation of an organism through means of reproduction, whether through asexual reproduction or sexual reproduction....
: a mosquito
Mosquito

Mosquitoes are common flying insects in the family Culicidae that are found around the world. There are about 3,500 species. They have a pair of scaled wings, a pair of halteres, a slender body, and six long legs....
 vector
Vector (biology)

In epidemiology, a vector is an organism that does not cause disease itself but that transmits infection by conveying pathogens from one Host to another, serving as a transmission ....
 and a vertebrate
Vertebrate

Vertebrates are members of the subphylum Vertebrata, chordates with Vertebras or Vertebral columns. The grouping sometimes includes the hagfish, which have no vertebrae, but are genetically quite closely related to lampreys, which do have vertebrae....
 host.

The genus is currently in need of reorganization as it has been shown that parasites belonging to the genera Haemoproteus
Haemoproteus

Haemoproteus is a genus of protozoa that are parasitic in birds, reptiles and amphibians. The genus created was by Kruse in 1890. Its name is derived from Greek language: Haima - blood and Proteus - a sea god who had the power of assuming different shapes....
 and Hepatocystis appear to be closely related to Plasmodium. It is likely that other species such as Haemoproteus meleagridis will be included in this genus once it is revised.

History


The organism itself was first seen by Laveran
Charles Louis Alphonse Laveran

Charles Louis Alphonse Laveran was a France physician.In 1880, while working in the military hospital in Constantine, Algeria, he discovered that the cause of malaria is a protozoan, after observing the parasites in a blood smear taken from a patient who had just died of malaria....
 on November 6 1880 at a military hospital in Constantine, Algeria
Constantine, Algeria

Constantine is the capital of Constantine Province in north-eastern Algeria. Slightly inland, it is about 80 kilometers from the Mediterranean Sea coast....
, when he discovered a microgametocyte exflagellating. In 1885 similar organisms were discovered within the blood of birds in Russia. There was brief speculation that birds might be involved in the transmission of malaria. Patrick Manson
Patrick Manson

Sir Patrick Manson was a Great Britain physician who made important discoveries in parasitology and was the founder of the tropical medicine field....
 (in 1894) hypothesised that mosquito
Mosquito

Mosquitoes are common flying insects in the family Culicidae that are found around the world. There are about 3,500 species. They have a pair of scaled wings, a pair of halteres, a slender body, and six long legs....
es could transmit malaria. This hypothesis was experimentally confirmed independently by the Italian professor Giovanni Battista Grassi
Giovanni Battista Grassi

Giovanni Battista Grassi was an Italy zoologist, known for work demonstrating that mosquitos carry the malaria plasmodium in their digestive tract, on the embryological development of honey bees, on parasites, particularly the vine parasite phylloxera, migrations and metamorphosis in eels, and on termites....
 and the British physician Ronald Ross
Ronald Ross

Sir Ronald Ross Knight Commander of the Order of the Bath was an Anglo-Indian physician. He was awarded the Nobel prize for Physiology or Medicine in 1902 for discovering the life cycle of the malarial parasite Plasmodium....
, both in 1898. Ross demonstrated the existence of Plasmodium in the wall of the midgut
Midgut

The midgut is the portion of the embryo from which most of the intestines are derived. After it bends around the superior mesenteric artery, it is called the "midgut loop"....
 and salivary glands of a Culex
Culex

Culex is a genus of mosquito, and several species act as Vector of important diseases, such as West Nile virus, filariasis, Japanese encephalitis, St....
 mosquito using bird species as the vertebrate host. For this discovery he won the Nobel Prize
Nobel Prize

The Nobel Prize , established in the 1895 will of Swedish chemist Alfred Nobel; it was first awarded in Nobel Prize in Physics, Nobel Prize in Chemistry, Nobel Prize in Physiology or Medicine, Nobel Prize in Literature, and Nobel Peace Prize in 1901....
 in 1902. Grassi showed that human malaria could only be transmitted by Anopheles
Anopheles

Anopheles is a genus of mosquito . There are approximately 460 recognised species: while over 100 can transmit human malaria, only 30-40 commonly transmit parasites of the genus Plasmodium that cause malaria which affects humans in endemic areas....
 mosquitoes. It is worth noting, however, that for some species the vector may not be a mosquito.

Grassi also proposed in 1900 the existence of an exerythrocytic stage in the life cycle: this was later confirmed by Short, Garnham, Covell and Shute (in 1948) who found Plasmodium vivax
Plasmodium vivax

Plasmodium vivax is a protozoal parasite and a human pathogen. The most frequent and widely distributed cause of recurring malaria, P. vivax is one of four species of malarial parasite that commonly infect in humans....
 in the human liver.

Life cycle


Mosquitoes of the genera Culex
Culex

Culex is a genus of mosquito, and several species act as Vector of important diseases, such as West Nile virus, filariasis, Japanese encephalitis, St....
, Anopheles
Anopheles

Anopheles is a genus of mosquito . There are approximately 460 recognised species: while over 100 can transmit human malaria, only 30-40 commonly transmit parasites of the genus Plasmodium that cause malaria which affects humans in endemic areas....
, Culiceta, Mansonia and Aedes
Aedes

Aedes is a genus of mosquito originally found in tropical and subtropical zones, but has spread by human activity to all continents excluding Antarctica....
 may act as vectors. The currently known vectors for human malaria (> 100 species) all belong to the genus Anopheles. Bird malaria is commonly carried by species belonging to the genus Culex. Only female mosquitoes bite. Aside from blood both sexes live on nectar, but one or more blood meals are needed by the female for egg laying as the protein content of nectar is very low. The life cycle of Plasmodium was discovered by Ross who worked with species from the genus Culex.

The life cycle of Plasmodium is complex. Sporozoite
Sporozoite

In the life-cycle of apicomplexan protozoa, sporozoites are cells that infect new hosts. In the parasites that cause malaria , for instance, the sporozoites are cells that develop in the mosquito's salivary glands, leave the mosquito during a blood meal, and enter the liver where they multiply....
s from the saliva of a biting female mosquito are transmitted to either the blood or the lymphatic system of the recipient. The sporozoites then migrate to the liver
Liver

The liver is a vital organ present in vertebrates and some other animals; it has a wide range of functions, a few of which are detoxification, protein synthesis, and production of biochemicals necessary for digestion....
 and invade hepatocyte
Hepatocyte

Hepatocytes make up 70-80% of the cytoplasmic mass of the liver.These cells are involved in protein synthesis, protein storage and transformation of carbohydrates, synthesis of cholesterol, bile salts and phospholipids, and detoxification, modification and excretion of exogenous and endogenous substances....
s. This latent or dormant stage of the Plasmodium sporozoite in the liver is known as a hypnozoite.

The development from the hepatic stages to the erythrocytic stages has until very recently been obscure. In 2006 it was shown that the parasite buds off the hepatocytes in merosomes containing hundreds or thousands of merozoites. These merosomes have been subsequently shown to lodge in the pulmonary capilaries and to slowly disintegrate there over 48–72 hours releasing merozoites. Erythrocyte invasion is enhanced when blood flow is slow and the cells are tightly packed: both of these conditions are found in the alveolar capilaries.

Within the erythrocytes the merozoite grow first to a ring-shaped form and then to a larger trophozoite
Trophozoite

A trophozoite is the activated, feeding stage in the life cycle of protozoan parasites such as the malaria-causing Plasmodium falciparum ....
 form. In the schizont stage, the parasite divides several times to produce new merozoites, which leave the red blood cells and travel within the bloodstream to invade new red blood cells. The parasite feeds by ingesting haemoglobin and other materials from red blood cells and serum. The feeding process damages the erythrocytes. Details of this process have not been studied in species other than Plasmodium falciparum
Plasmodium falciparum

Plasmodium falciparum is a protozoan parasite, one of the species of Plasmodium that cause malaria in humans. It is transmitted by the female...
 so generalisations may be premature at this time.

At the molecular level a set of enzymes known as plasmepsin
Plasmepsin

Plasmepsins are a class of at least 10 enzymes produced by the plasmodium parasite.There are ten different isoforms of these proteins and ten genes...
s which are aspartic acid proteases
Protease

A protease is any enzyme that conducts proteolysis, that is, begins protein catabolism by hydrolysis of the peptide bonds that link amino acids together in the polypeptide chain, which form a molecule of protein....
 are used to degrade hemoglobin
Hemoglobin

Hemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells of vertebrates, and the tissues of some invertebrates....
. The parasite digests 70-80% of the erythrocyte's haemoglobin but utilises only ~15% in de novo protein synthesis Intraerythrocytic Plasmodium falciparum utilizes only a fraction of the amino acids derived from the digestion of host cell cytosol for the biosynthesis of its proteins. The excess amino acids are exported from the infected erythrocyte by new transport pathways created by the parasite. The reason proposed for this apparently excessive digestion of haemoglobin is the colloid-osmotic hypothesis which suggests that the digestion of haemoglobin increases the osmotic pressure within the infected erythrocyte leading to its premature rupture and subsequent death of the parasite. To avoid this fate much of the haemoglobin is digested and exported from the erythrocyte. This hypothesis has been experimentally confirmed.

Most merozoites continue this replicative cycle, but some merozoites differentiate into male or female sexual forms (gametocyte
Gametocyte

A gametocyte is a eukaryotic germ cell that divides by mitosis into other gametocytes or by meiosis into gametids during gametogenesis. Male gametocytes are called spermatocytes, and female gametocytes are called oocytes....
s) (also in the blood), which are taken up by the female mosquito.

In the mosquito's midgut, the gametocyte
Gametocyte

A gametocyte is a eukaryotic germ cell that divides by mitosis into other gametocytes or by meiosis into gametids during gametogenesis. Male gametocytes are called spermatocytes, and female gametocytes are called oocytes....
s develop into gamete
Gamete

A gamete is a Cell that fuses with another gamete during fertilization in organisms that sexual reproduction. In species which produce two morphologically distinct types of gametes, and in which each individual produces only one type, a female is any individual which produces the larger type of gamete?called an ovum ?and a male produces th...
s and fertilize each other, forming motile zygote
Zygote

A zygote is a cell that is the result of fertilization. That is, two ploidy cells—usually an ovum from a female and a sperm cell from a male—merge into a single ploidy cell called the zygote ....
s called ookinetes. The ookinetes penetrate and escape the midgut, then embed themselves onto the exterior of the gut membrane. Here they divide many times to produce large numbers of tiny elongated sporozoite
Sporozoite

In the life-cycle of apicomplexan protozoa, sporozoites are cells that infect new hosts. In the parasites that cause malaria , for instance, the sporozoites are cells that develop in the mosquito's salivary glands, leave the mosquito during a blood meal, and enter the liver where they multiply....
s. These sporozoites migrate to the salivary glands of the mosquito where they are injected into the blood and subcutaneous tissue of the next host the mosquito bites. The majority appear to be injected into the subcutaneous tissue from which they migrate into the capillaries. A proportion are ingested by macrophages and still others are taken up by the lymphatic system where they are presumably destroyed. The sporozoites which successfully enter the blood stream move to the liver where they begin the cycle again.

The pattern of alternation of sexual and asexual reproduction which may seem confusing at first is a very common pattern in parasitic species. The evolutionary advantages of this type of life cycle were recognised by Mendel.

Under favourable conditions asexual reproduction is superior to sexual as the parent is well adapted to its environment and its descendents share these genes. Transferring to a new host or in times of stress, sexual reproduction is generally superior as this produces a shuffling of genes
Gênes

G?nes is the name of a d?partement in France of the First French Empire in present Italy. It was named after the city Genoa. It was formed in 1805, when Napoleon Bonaparte occupied the Republic of Genoa....
 which on average at a population level will produce individuals better adapted to the new environment.

Reactivation of the hypnozoites has been reported for up to 30 years after the initial infection in humans. The factors precipating this reactivation are not known. In the species Plasmodium malariae
Plasmodium malariae

Introduction Plasmodium malariae is a parasite protozoa that causes malaria in humans. It is closely related to Plasmodium falciparum and Plasmodium vivax which are responsible for most malarial infection....
, Plasmodium ovale
Plasmodium ovale

Plasmodium ovale is a species of parasite protozoa that causes tertian malaria in humans. It is closely related to Plasmodium falciparum and Plasmodium vivax, which are responsible for most malaria....
 and Plasmodium vivax
Plasmodium vivax

Plasmodium vivax is a protozoal parasite and a human pathogen. The most frequent and widely distributed cause of recurring malaria, P. vivax is one of four species of malarial parasite that commonly infect in humans....
 hypnozoites have been shown to occur. Reactivation was not thought to occur in infections with Plasmodium falciparum
Plasmodium falciparum

Plasmodium falciparum is a protozoan parasite, one of the species of Plasmodium that cause malaria in humans. It is transmitted by the female...
 but there are been two reports to date suggesting that this may occur (see below) . It is not known if hypnozoite reactivaction may occur with any of the remaining species that infect humans but this is presumed to be the case.

A report of recurrence of P. falciparum in a patient with sickle cell anaemia has been published but this needs confirmation as hypnozoites are not known to occur in P. falciparum infections. A second report of P. falciparum malaria eight years after leaving an endemic area has also been published. While this is consistent with the existence of a hypnozoite stage additional confirmation seems desirable.

A third case of an apparent recurrence of P. falciparum malaria 9 years after leaving an endemic area has now been reported. It is beginning to appear that at least occasionally P. falciparum has a hypnozoite stage. If this is in fact the case eradication or even control of this organism may be more difficult than has previously believed.

Evolution


The life cycle is probably best understood in terms of its evolution
Evolution

In biology, evolution is change in the heritability trait of a population of organisms from one generation to the next. These changes are caused by a combination of three main processes: variation, reproduction, and selection....
. At the present time (2007) DNA sequences are available from fewer than sixty species of Plasmodium and most of these are from species infecting either rodent or primate hosts. The evolutionary outline given here should be regarded as speculative and subject to revision as data becomes available.

The Apicomplexa
Apicomplexa

The Apicomplexa are a large group of protists, characterized by the presence of a unique organelle called an apical complex . They are unicellular, spore-forming, and exclusively parasites of animals....
 — the phylum to which Plasmodium
Plasmodium

Plasmodium is a genus of parasitic protozoa. Infection with these parasites is known as malaria. The genus Plasmodium was created in 1885 by Ettore Marchiafava and Angelo Celli....
 belongs - are thought to have originated within the Dinoflagellate
Dinoflagellate

The dinoflagellates are a large group of flagellate protists. Most are marine plankton, but they are common in fresh water habitats as well. Their populations are distributed depending on sea surface temperature, salinity, or depth....
s — a large group of photosynthetic protozoa. It is thought that the ancestors of the Apicomplexa were originally prey organisms that evolved the ability to invade the intestinal cells and subsequently lost their photosynthetic ability. Many of the species within the Apicomplexia still possess a plastid (the organelle in which photosynthesis occurs in eukaryotes): some that do not have evidence of plastid genes within their genome. These plastids - unlike those found in algae
Algae

Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms. The largest and most complex marine forms are called seaweeds....
 - are not photosynthetic. Its function is not known but there is some suggestive evidence that it may be involved in reproduction.

Some extant dinoflagelates, however, can invade the bodies of jellyfish
Jellyfish

Jellyfish are free-swimming members of the phylum Cnidaria. They have several different morphologies that represent several different cnidarian classes including the Scyphozoa , Staurozoa , Cubozoa , and Hydrozoa ....
 and continue to photosynthesize, which is possible because jellyfish bodies are almost transparent. In other organisms with opaque
Opacity (optics)

Opacity is the measure of impenetrability to electromagnetic radiation or other kinds of radiation, especially visible light. In radiative transfer, it describes the absorption and scattering of radiation in a medium, such as a plasma, dielectric, radiation shield, glass, etc....
 bodies this ability would most likely rapidly be lost. The recent (2008) description of a photosynthetic protist related to the Apicomplexia with a functional plastid supports this hypothesis.

Current (2007) theory suggests that the genera Plasmodium, Hepatocystis and Haemoproteus
Haemoproteus

Haemoproteus is a genus of protozoa that are parasitic in birds, reptiles and amphibians. The genus created was by Kruse in 1890. Its name is derived from Greek language: Haima - blood and Proteus - a sea god who had the power of assuming different shapes....
 evolved from one or more Leukocytozoon
Leukocytozoon

Leukocytozoon is a genus of parasitic protozoa belonging to the phylum Apicomplexia. The parasites were first seen by Danilewsky in 1884. The genus was created by Ziemann in 1898....
 species. Parasites of the genus Leukocytozoan infect white blood cells (leukocytes), liver
Liver

The liver is a vital organ present in vertebrates and some other animals; it has a wide range of functions, a few of which are detoxification, protein synthesis, and production of biochemicals necessary for digestion....
 and spleen
Spleen

The spleen is an organ found in all vertebrate animals. In humans, the spleen is located in the abdomen of the body, where it functions in the destruction of redundant red blood cells, and holds a reservoir of blood....
 cells and are transmitted by 'black flies' (Simulium
Simulium

Simulium is a genus of black fly. It is an immense genus with several hundred species, and many sub-genera....
 species) — a large genus of flies related to the mosquitoes.

It is thought that Leukocytozoon evolved from a parasite that spread by the orofaecal route and which infected the intestinal wall. At some point this parasite evolved the ability to infect the liver
Liver

The liver is a vital organ present in vertebrates and some other animals; it has a wide range of functions, a few of which are detoxification, protein synthesis, and production of biochemicals necessary for digestion....
. This pattern is seen in the genus Cryptosporidium to which Plasmodium is distantly related. At some later point this ancestor developed the ability to infect blood cells and to survive and infect mosquito
Mosquito

Mosquitoes are common flying insects in the family Culicidae that are found around the world. There are about 3,500 species. They have a pair of scaled wings, a pair of halteres, a slender body, and six long legs....
es. Once vector transmission was firmly established the previous orofecal route of transmission was lost.

Leukocytes, hepatocyte
Hepatocyte

Hepatocytes make up 70-80% of the cytoplasmic mass of the liver.These cells are involved in protein synthesis, protein storage and transformation of carbohydrates, synthesis of cholesterol, bile salts and phospholipids, and detoxification, modification and excretion of exogenous and endogenous substances....
s and most spleen cells actively phagocytose particulate matter making entry into the cell easier for the parasite. The mechanism of entry of Plasmodium species into erythrocytes is still very unclear taking as it does less than 30 seconds. It is not yet known if this mechanism evolved before mosquitoes became the main vectors for transmission of Plasmodium.

The genus Plasmodium evolved (presumably from its Leukocytozoon ancestor) about 130 million years ago, a period that is coincidental with the rapid spread of the angiosperms (flowering plants). This expansion in the angiosperms is thought to be due to at least one genomic duplication event. It seems probable that the increase in the number of flowers led to an increase in the number of mosquitoes and their contact with vertebrates.

Mosquitoes evolved in what is now South America
South America

South America is the southern continent of the Americas, situated entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere....
 about 230 million years ago. There are over 3500 species recognised but to date their evolution has not been well worked out so a number of gaps in our knowledge of the evolution of Plasmodium remain. There is evidence of a recent expansion of Anopheles gambiae
Anopheles gambiae

Anopheles gambiae, refers to a cryptic species complex of morphologically indistinguishable mosquitoes in the genus Anopheles, which contains the most important vectors of malaria in Sub-Saharan Africa , and the most efficient malaria vectors in the world....
 and Anopheles arabiensis populations in the late Pleistocene
Pleistocene

The Pleistocene is the epoch from 1.8 million to 10,000 years Before Present covering the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
 in Nigeria
Nigeria

Nigeria, officially the Federal Republic of Nigeria, is a federation constitutional republic comprising States of Nigeria and one Federal Capital Territory, Nigeria....
.

Presently it seems probable that birds were the first group infected by Plasmodium followed by the reptiles—probably the lizards. At some point primates and rodents became infected. The remaining species infected outside these groups seem likely to be due to relatively recent events.

Biology


All Plasmodium species examined to date have 14 chromosomes, one mitochondrion
Mitochondrion

In cell biology, a mitochondrion is a membrane-enclosed organelle found in most eukaryote cell . These organelles range from 0.5–10 micrometers in diameter....
 and one plastid
Plastid

Plastids are major organelles found in plants and algae. Plastids are the site of manufacture and storage of important chemical compounds used by the cell....
. The chromosomes whose length is known vary from 500 kilobases to 3.5 megabases in length. It is presumed that this is the pattern throughout the genus. The typical chormosome number of Leukcytozoon has not yet been established.

The genome of four Plasmodium species have been sequenced. These species are Plasmodium falciparum
Plasmodium falciparum

Plasmodium falciparum is a protozoan parasite, one of the species of Plasmodium that cause malaria in humans. It is transmitted by the female...
, Plasmodium knowlesi
Plasmodium knowlesi

File:Anophelesmosquito.pngPlasmodium knowlesi is a primate malaria parasite commonly found in Southeast Asia. It causes malaria in long-tailed macaques , but it may also infect humans, either naturally or artificially....
, Plasmodium vivax
Plasmodium vivax

Plasmodium vivax is a protozoal parasite and a human pathogen. The most frequent and widely distributed cause of recurring malaria, P. vivax is one of four species of malarial parasite that commonly infect in humans....
 and Plasmodium yoelli. All these species have 14 chromosomes and genomes of about 25 megabases results consistent with earlier estimates.

The biology of these organisms is more fully described on the Plasmodium falciparum biology page
Plasmodium falciparum biology

Plasmodium falciparum has been the focus of much research due to it being the causative agent of malaria. This article describes some of the recent findings surrounding the unique biology of this organism....
.

Taxonomy


Plasmodium belongs to the family
Family

Family denotes a group of people affiliated by a common ancestry, affinity or co-residence. Although the concept of consanguinity originally referred to relations by "blood," some cultural anthropology have argued that one must understand the idea of "blood" metaphorically, and that many societies understand 'family' through other concepts r...
 Plasmodiidae
Plasmodiidae

The Plasmodiidae are a family of apicomplexan parasites, including the type genus Plasmodium, which is responsible for malaria. They are given their own Order - the Haemosporida....
 (Levine, 1988), order
Order (biology)

In Biological classification used in biology, the order is a taxonomic rank between class and family . The superorder is a rank between class and order....
 Haemosporidia and phylum
Phylum

A phylum "Phylum" is adopted from the Greek phylai, the clan-based voting groups in Greek city-states. is a taxonomic rank below Kingdom and above Class ....
 Apicomplexa
Apicomplexa

The Apicomplexa are a large group of protists, characterized by the presence of a unique organelle called an apical complex . They are unicellular, spore-forming, and exclusively parasites of animals....
. There are currently 450 recognised species
Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring....
 in this order. Many species of this order are undergoing reexamination of their taxonomy with DNA
DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetics instructions used in the development and functioning of all known living organisms and some viruses....
 analysis. It seems likely that many of these species will be re-assigned after these studies have been completed. For this reason the entire order is outlined here.

Order Haemosporida

  • Genus Bioccala
    Bioccala

    Bioccala is a genus of parasitic protozoa belonging to the phylum Apicomplexia....


Family Haemoproteidae

  • Genus Haemoproteus
    Haemoproteus

    Haemoproteus is a genus of protozoa that are parasitic in birds, reptiles and amphibians. The genus created was by Kruse in 1890. Its name is derived from Greek language: Haima - blood and Proteus - a sea god who had the power of assuming different shapes....
    • Subgenus Parahaemoproteus
    • Subgenus Haemoproteus
      Haemoproteus

      Haemoproteus is a genus of protozoa that are parasitic in birds, reptiles and amphibians. The genus created was by Kruse in 1890. Its name is derived from Greek language: Haima - blood and Proteus - a sea god who had the power of assuming different shapes....


Family Garniidae

  • Genus Fallisia
    • Subgenus Plasmodioides


Family Leucocytozoidae

  • Genus Leukocytozoon
    Leukocytozoon

    Leukocytozoon is a genus of parasitic protozoa belonging to the phylum Apicomplexia. The parasites were first seen by Danilewsky in 1884. The genus was created by Ziemann in 1898....
    • Subgenus Leucocytozoon
    • Subgenus Akiba
      Akiba

      Akiba Also pronounced Akiva can refer to:*The Aramaic form of the name Jacob.*Akiba-Schechter Jewish Day School, a Jewish school in Hyde Park, Chicago...


Family Plasmodiidae
Plasmodiidae

The Plasmodiidae are a family of apicomplexan parasites, including the type genus Plasmodium, which is responsible for malaria. They are given their own Order - the Haemosporida....


  • Genus Billbraya
  • Genus Dionisia
    Dionisia

    Dionisia is a genus of parasitic protozoa belonging to the phylum Apicomplexia.The type species of this genus is Dionisia bunoi....
  • Genus Hepatocystis
  • Genus Mesnilium
  • Genus Nycteria


  • Genus Plasmodium
    • Subgenus Asiamoeba
    • Subgenus Bennettinia
      Bennettinia

      Bennettinia is a subgenus of the genus Plasmodium - all of which are parastic protozoa. The subgenus was created in 1997 by Valkiunas. Species in this subgenus infect birds....
    • Subgenus Carinamoeba
      Carinamoeba

      Carinamoeba is a subgenus of the genus Plasmodium - all of which are parastic protozoa. The subgenus was created in 1966 by Garnham. Species in this subgenus infect reptiles....
    • Subgenus Giovannolaia
      Giovannolaia

      Giovanolaia is a subgenus of the genus Plasmodium created by Corradetti et al in 1963. The parasites within this subgenus infect birds....
    • Subgenus Haemamoeba
      Haemamoeba

      Haemamoeba is a subgenus of the genus Plasmodium - all of which are parastic protozoa. The subgenus was created in 1963 by created by Corradetti et al....
    • Subgenus Huffia
      Huffia

      Huffia is a subgenus of the genus Plasmodium - all of which are parasitic protozoa. The subgenus was created in 1963 by Corradetti et al....
    • Subgenus Lacertaemoba
      Lacertaemoba

      Lacertaemoba is a subgenus of the genus Plasmodium - all of which are parasitic protozoa. All species in this subgenus infect reptiles....
    • Subgenus Laverania
      Laverania

      Laverania is a subgenus of the genus Plasmodium. The subgenus was created in 1958 by Bray. The subgenus contains only species: Plasmodium falciparum and Plasmodium reichenowi....
    • Subgenus Novyella
      Novyella

      Novyella is a subgenus of the genus Plasmodium - all of which are parastic protozoa. The subgenus was created in 1963 by created by Corradetti et al....
    • Subgenus Plasmodium
      Plasmodium

      Plasmodium is a genus of parasitic protozoa. Infection with these parasites is known as malaria. The genus Plasmodium was created in 1885 by Ettore Marchiafava and Angelo Celli....
    • Subgenus Paraplasmodium
    • Subgenus Sauramoeba
      Sauramoeba

      Sauramoeba is a subgenus of the genus Plasmodium - all of which are parastic protozoa. The subgenus was created in 1966 by Garnham. Species in this subgenus infect reptiles....
    • Subgenus Vinckeia
      Vinckeia

      Vinckeia is a subgenus of the genus Plasmodium - all of which are parastic protozoa. The subgenus Vinckeia was created by Garnham in 1966 to accommodate the mammalian parasites other than those infecting the primates....


  • Genus Polychromophilus
  • Genus Rayella
  • Genus Saurocytozoon


Diagnostic characteristics of the genus Plasmodium


  • Merogony occurs both in erythrocytes and other tissues
  • Merozoites, schizonts or gametocytes can be seen within erythrocytes and may displace the host nucleus
  • Merozoites have a “signet-ring” appearance due to a large vacuole that forces the parasite’s nucleus to one pole
  • Schizonts are round to oval inclusions that contain the deeply staining merozoites
  • Forms gamonts in erythrocytes
  • Gametocytes are 'halter-shaped' similar to Haemoproteus
    Haemoproteus

    Haemoproteus is a genus of protozoa that are parasitic in birds, reptiles and amphibians. The genus created was by Kruse in 1890. Its name is derived from Greek language: Haima - blood and Proteus - a sea god who had the power of assuming different shapes....
     but the pigment granules are more confined
  • Hemozoin is present
  • Vectors are either mosquitos or sandflies
  • Vertebrate hosts include mammals, birds and reptiles


Notes:

The genera Plasmodium, Fallisia and Saurocytozoon all cause malaria in lizards. All are carried by Diptera (flies). Pigment is absent in the Garnia. Non pigmented gametocytes are typically the only forms found in Saurocytozoon: pigmented forms may be found in the leukocytes occasionally. Fallisia produce non pigmented asexual and gametocyte forms in leukocytes and thrombocytes.

Phylogenetic trees


The relationship between a number of these species can be seen on the . Perhaps the most useful inferences that can be drawn from this phylogenetic tree
Phylogenetic tree

A phylogenetic tree or evolutionary tree is a tree showing the evolutionary relationships among various biological species or other entities that are believed to have a common descent....
 are:

  • P. falciparum and P. reichenowi (subgenus Laverania) branched off early in the evolution of this genus
  • The genus Hepatocystis is nested within (paraphytic with) the genus Plasmodium
  • The primate (subgenus Plasmodium) and rodent species (subgenus Vinckeia) form distinct groups
  • The rodent and primate groups are relatively closely related
  • The lizard and bird species are intermingled
  • Although Plasmodium elongatum (subgenus Haemamoeba) and Plasmodium elongatum (subgenus Huffia) appear be related here there are so few bird species (three) included, this tree may not accurately reflect their real relationship.
  • While no snake parasites have been included these are likely to group with the lizard-bird division


While this tree contains a considerable number of species, DNA sequences from many species in this genus have not been included - probably because they are not available yet. Because of this problem, this tree and any conclusions that can be drawn from it should be regarded as provisional.

Three additional trees are available from the .

These trees agree with the Tree of Life. Because of there greater number of species in these trees, some additional inferences can be made:

  • The genus Hepatocystis appears to lie within the primate-rodent clade
  • The genus Haemoproteus appears lie within the bird-lizard clade
  • The trees are consistent with the proposed origin of Plasmodium from Leukocytozoon


Subgenera: discussion


The full taxonomic name of a species includes the subgenus but this is often omitted. The full name indicates some features of the morphology and type of host species.

The only two species in the sub genus Laverania
Laverania

Laverania is a subgenus of the genus Plasmodium. The subgenus was created in 1958 by Bray. The subgenus contains only species: Plasmodium falciparum and Plasmodium reichenowi....
 are P. falciparum and P. reichenowi. The presence of elongated gametocytes in several of the avian subgenera and in Laverania in addition to a number of clinical features suggested that these might be closely related. This is is no longer thought to be the case.

Species infecting monkey
Monkey

A monkey is a nonhuman primate mammal with the exception usually of the lemurs and tarsiers. More specifically, the term monkey refers to a subset of monkeys: any of the smaller longer-tailed catarrhine or platyrrhine primates as contrasted with the apes....
s and apes (the higher primates) with the exceptions of P. falciparum and P. reichenowi are classified in the subgenus Plasmodium. The distinction between P. falciparum and P. reichenowi and the other species infecting higher primates was based on the morphological findings but have since been confirmed by DNA analysis.

Parasites infecting other mammal
Mammal

Mammals are a class of vertebrate animals whose name is derived from their distinctive feature, mammary glands, with which they feed their young....
s including lower primates (lemur
Lemur

Lemurs make up the infraorder Lemuriformes and are members of a group of primates known as prosimians. The term "lemur" is derived from the Latin word lemures, meaning "spirits of the night" or "ghosts"....
s and others) are classified in the subgenus Vinckeia
Vinckeia

Vinckeia is a subgenus of the genus Plasmodium - all of which are parastic protozoa. The subgenus Vinckeia was created by Garnham in 1966 to accommodate the mammalian parasites other than those infecting the primates....
. Vinckeia while previously considered to be something of a taxonomic 'rag bag' has been recently shown - perhaps rather surprisingly - to form a coherent grouping.

The remaining groupings are based on the morphology of the parasites. Revisions to this system are likely to occur in the future as more species are subject to analysis of their DNA
DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetics instructions used in the development and functioning of all known living organisms and some viruses....
.

The four subgenera Giovannolaia
Giovannolaia

Giovanolaia is a subgenus of the genus Plasmodium created by Corradetti et al in 1963. The parasites within this subgenus infect birds....
, Haemamoeba
Haemamoeba

Haemamoeba is a subgenus of the genus Plasmodium - all of which are parastic protozoa. The subgenus was created in 1963 by created by Corradetti et al....
, Huffia
Huffia

Huffia is a subgenus of the genus Plasmodium - all of which are parasitic protozoa. The subgenus was created in 1963 by Corradetti et al....
 and Novyella
Novyella

Novyella is a subgenus of the genus Plasmodium - all of which are parastic protozoa. The subgenus was created in 1963 by created by Corradetti et al....
 were created by Corradetti et al for the known avian malarial species. A fifth - Bennettinia
Bennettinia

Bennettinia is a subgenus of the genus Plasmodium - all of which are parastic protozoa. The subgenus was created in 1997 by Valkiunas. Species in this subgenus infect birds....
 - was created in 1997 by Valkiunas. The relationships between the subgenera are the matter of current investigation. Martinsen et al 's recent (2006) paper outlines what is currently (2007) known. The subgenera Haemamoeba, Huffia, and Bennettinia appear to be monphylitic. Novyella appears to be well defined with occasional exceptions. The subgenus Giovannolaia needs revision.

P. juxtanucleare is currently (2007) the only known member of the subgenus Bennettinia.

Unlike the mammalian and bird malarias those affecting reptiles have been more difficult to classify. In 1966 Garnham classified those with large schizonts as Sauramoeba
Sauramoeba

Sauramoeba is a subgenus of the genus Plasmodium - all of which are parastic protozoa. The subgenus was created in 1966 by Garnham. Species in this subgenus infect reptiles....
, those with small schizonts as Carinamoeba
Carinamoeba

Carinamoeba is a subgenus of the genus Plasmodium - all of which are parastic protozoa. The subgenus was created in 1966 by Garnham. Species in this subgenus infect reptiles....
 and the single then known species infecting snakes (Plasmodium wenyoni
Plasmodium wenyoni

Plasmodium wenyoni is a parasite of the genus Plasmodium.Like all Plasmodium species P. wenyoni has both vertebrate and insect hosts....
) as Ophidiella
Ophidiella

Ophidiella is a defunct subgenus of the genus Plasmodium. The subgenus was created in 1966 by Garnham. .It was created as a subgenus for the then only known species infecting snakes - Plasmodium wenyoni but is currently not in use....
. He was aware of the arbitrariness of this system and that it might not prove to be biologically valid. Telford in 1988 used this scheme as the basis for the currently accepted (2007) system.

Classification criteria for subgenera


Species in the subgenus Giovannolaia
Giovannolaia

Giovanolaia is a subgenus of the genus Plasmodium created by Corradetti et al in 1963. The parasites within this subgenus infect birds....
 have the following characteristics:

  • Schizonts contain plentiful cytoplasm, are larger than the host cell nucleus and frequently displace it. They are found only in mature erythrocytes.
  • Gametocytes are elongated.
  • Exoerythrocytic schizogony occurs in the mononuclear phagocyte system.


Species in the subgenus Haemamoeba
Haemamoeba

Haemamoeba is a subgenus of the genus Plasmodium - all of which are parastic protozoa. The subgenus was created in 1963 by created by Corradetti et al....
 have the following characteristics:

  • Mature schizonts are larger than the host cell nucleus and commonly displace it.
  • Gametocytes are large, round, oval or irregular in shape and are substantially larger than the host nucleus.


Species in the subgenus Huffia
Huffia

Huffia is a subgenus of the genus Plasmodium - all of which are parasitic protozoa. The subgenus was created in 1963 by Corradetti et al....
 have the following characteristics:

  • Mature schizonts, while varying in shape and size, contain plentiful cytoplasm and are commonly found in immature erthryocytes.
  • Gametocytes are elongated.


Species in the subgenus Novyella
Novyella

Novyella is a subgenus of the genus Plasmodium - all of which are parastic protozoa. The subgenus was created in 1963 by created by Corradetti et al....
 have the following characteristics:

  • Mature schisonts are either smaller than or only slightly larger than the host nucleus. They contain scanty cytoplasm.
  • Gametocytes are elongated. Sexual stages in this subgenus resemble those of Haemoproteus.
  • Exoerythrocytic schizogony occurs in the mononuclear phagocyte system


Reptile species


Species in the subgenus Carinamoeba
Carinamoeba

Carinamoeba is a subgenus of the genus Plasmodium - all of which are parastic protozoa. The subgenus was created in 1966 by Garnham. Species in this subgenus infect reptiles....
 have the following characteristics:

  • Infect lizards
  • Schizonts normally give rise to less than 8 merozoites


Species in the subgenus Sauramoeba
Sauramoeba

Sauramoeba is a subgenus of the genus Plasmodium - all of which are parastic protozoa. The subgenus was created in 1966 by Garnham. Species in this subgenus infect reptiles....
 have the following characteristics:

  • Infect lizards
  • Schizonts normally give rise to more than 8 merozoites


Notes

  • The erythrocytes of both reptiles and birds retain their nucleus, unlike those of mammals. The reason for the loss of the nucleus in mammalian erythocytes remains unknown.


Species listed by subgenera


Plasmodium (Asiamoeba) draconis
Plasmodium (Asiamoeba) vastator

Plasmodium (Bennettinia) juxtanucleare

Plasmodium (Carinamoeba) basilisci
Plasmodium (Carinamoeba) clelandi
Plasmodium (Carinamoeba) lygosomae
Plasmodium (Carinamoeba) mabuiae
Plasmodium (Carinamoeba) minasense
Plasmodium (Carinamoeba) rhadinurum
Plasmodium (Carinamoeba) volans

Plasmodium (Giovannolaia) anasum
Plasmodium (Giovannolaia) circumflexum
Plasmodium (Giovannolaia) dissanaikei
Plasmodium (Giovannolaia) durae
Plasmodium (Giovannolaia) fallax
Plasmodium (Giovannolaia) formosanum
Plasmodium (Giovannolaia) gabaldoni
Plasmodium (Giovannolaia) garnhami
Plasmodium (Giovannolaia) gundersi
Plasmodium (Giovannolaia) hegneri
Plasmodium (Giovannolaia) lophurae
Plasmodium (Giovannolaia) pedioecetii
Plasmodium (Giovannolaia) pinnotti
Plasmodium (Giovannolaia) polare

Plasmodium (Haemamoeba) cathemerium
Plasmodium (Haemamoeba) coggeshalli
Plasmodium (Haemamoeba) coturnixi
Plasmodium (Haemamoeba) elongatum
Plasmodium (Haemamoeba) gallinaceum
Plasmodium (Haemamoeba) giovannolai
Plasmodium (Haemamoeba) lutzi
Plasmodium (Haemamoeba) matutinum
Plasmodium (Haemamoeba) paddae
Plasmodium (Haemamoeba) parvulum
Plasmodium (Haemamoeba) relictum
Plasmodium (Haemamoeba) tejera

Plasmodium (Huffia) elongatum
Plasmodium (Huffia) hermani

Plasmodium (Lacertaemoba) floridense
Plasmodium (Lacertaemoba) tropiduri

Plasmodium (Laverania) falciparum
Plasmodium (Laverania) reichenowi

Plasmodium (Novyella) ashfordi
Plasmodium (Novyella) bertii
Plasmodium (Novyella) bambusicolai
Plasmodium (Novyella) columbae
Plasmodium (Novyella) corradettii
Plasmodium (Novyella) dissanaikei
Plasmodium (Novyella) globularis
Plasmodium (Novyella) hexamerium
Plasmodium (Novyella) jiangi
Plasmodium (Novyella) kempi
Plasmodium (Novyella) lucens
Plasmodium (Novyella) megaglobularis
Plasmodium (Novyella) multivacuolaris
Plasmodium (Novyella) nucleophilum
Plasmodium (Novyella) papernai
Plasmodium (Novyella) parahexamerium
Plasmodium (Novyella) paranucleophilum
Plasmodium (Novyella) rouxi
Plasmodium (Novyella) vaughani

Plasmodium (Paraplasmodium) chiricahuae
Plasmodium (Paraplasmodium) mexicanum
Plasmodium (Paraplasmodium) pifanoi

Plasmodium (Plasmodium) bouillize
Plasmodium (Plasmodium) brasilianum
Plasmodium (Plasmodium) cercopitheci
Plasmodium (Plasmodium) coatneyi
Plasmodium (Plasmodium) cynomolgi
Plasmodium (Plasmodium) eylesi
Plasmodium (Plasmodium) fieldi
Plasmodium (Plasmodium) fragile
Plasmodium (Plasmodium) georgesi
Plasmodium (Plasmodium) girardi
Plasmodium (Plasmodium) gonderi
Plasmodium (Plasmodium) inui
Plasmodium (Plasmodium) jefferyi
Plasmodium (Plasmodium) joyeuxi
Plasmodium (Plasmodium) knowlei
Plasmodium (Plasmodium) hyobati
Plasmodium (Plasmodium) malariae
Plasmodium (Plasmodium) ovale
Plasmodium (Plasmodium) petersi
Plasmodium (Plasmodium) pitheci
Plasmodium (Plasmodium) rhodiani
Plasmodium (Plasmodium) schweitzi
Plasmodium (Plasmodium) semiovale
Plasmodium (Plasmodium) semnopitheci
Plasmodium (Plasmodium) silvaticum
Plasmodium (Plasmodium) simium
Plasmodium (Plasmodium) vivax
Plasmodium (Plasmodium) youngi

Plasmodium (Sauramoeba) achiotense
Plasmodium (Sauramoeba) adunyinkai
Plasmodium (Sauramoeba) aeuminatum
Plasmodium (Sauramoeba) agamae
Plasmodium (Sauramoeba) beltrani
Plasmodium (Sauramoeba) brumpti
Plasmodium (Sauramoeba) cnemidophori
Plasmodium (Sauramoeba) diploglossi
Plasmodium (Sauramoeba) giganteum
Plasmodium (Sauramoeba) heischi
Plasmodium (Sauramoeba) josephinae
Plasmodium (Sauramoeba) pelaezi
Plasmodium (Sauramoeba) zonuriae

Plasmodium (Vinckeia) achromaticum
Plasmodium (Vinckeia) aegyptensis
Plasmodium (Vinckeia) anomaluri
Plasmodium (Vinckeia) atheruri
Plasmodium (Vinckeia) berghei
Plasmodium (Vinckeia) booliati
Plasmodium (Vinckeia) brodeni
Plasmodium (Vinckeia) bubalis
Plasmodium (Vinckeia) bucki
Plasmodium (Vinckeia) caprae
Plasmodium (Vinckeia) cephalophi
Plasmodium (Vinckeia) chabaudi
Plasmodium (Vinckeia) coulangesi
Plasmodium (Vinckeia) cyclopsi
Plasmodium (Vinckeia) foleyi
Plasmodium (Vinckeia) girardi
Plasmodium (Vinckeia) incertae
Plasmodium (Vinckeia) inopinatum
Plasmodium (Vinckeia) landauae
Plasmodium (Vinckeia) lemuris
Plasmodium (Vinckeia) melanipherum
Plasmodium (Vinckeia) narayani
Plasmodium (Vinckeia) odocoilei
Plasmodium (Vinckeia) percygarnhami
Plasmodium (Vinckeia) pulmophilium
Plasmodium (Vinckeia) sandoshami
Plasmodium (Vinckeia) traguli
Plasmodium (Vinckeia) tyrio
Plasmodium (Vinckeia) uilenbergi
Plasmodium (Vinckeia) vinckei
Plasmodium (Vinckeia) watteni
Plasmodium (Vinckeia) yoelli''

Notes

''Ophidiella
Ophidiella

Ophidiella is a defunct subgenus of the genus Plasmodium. The subgenus was created in 1966 by Garnham. .It was created as a subgenus for the then only known species infecting snakes - Plasmodium wenyoni but is currently not in use....
'' was a subgenus created by Garnham in 1966 for the species infecting snakes. Presently (2007) it is no longer in use.

Host range


Host range among the mammalian orders is non uniform. At least 29 species
Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring....
 infect non human primates; rodents outside the tropical parts of Africa
Africa

Africa is the world's second-largest and second most-populous continent, after Asia. At about 30.2 million km? including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area....
 are rarely affected; a few species are known to infect bat
Bat

Bats are mammals in the order Chiroptera. The forelimbs of all bats are developed as wings, making them the only mammals naturally capable of sustained flight ....
s, porcupine
Porcupine

Porcupines are rodents with a coat of sharp Spine , or quills, that defend them from predators. They are endemic in both the Old World and the New World....
s and squirrel
Squirrel

File:Eichh?rnchen D?sseldorf Hofgarten edit.jpgA squirrel is one of many small or medium-sized rodents in the family Sciuridae. In the English language-speaking world, squirrel commonly refers to members of this family's genus Sciurus and Tamiasciurus, which are tree squirrels with large bushy tails, indigenous to Asia, the America...
s; carnivore
Carnivore

A carnivore , meaning 'meat eater' , is any animal with a diet consisting mainly of meat, whether it comes from animals living or dead .In a more general sense, an animal may be considered a carnivore if it prefers feeding on animal matter over plant matter....
s, insectivore
Insectivore

An insectivore is a type of carnivore with a diet that consists chiefly of insects and similar small creatures.Although individually small, insects exist in enormous numbers and make up a very large part of the animal biomass in almost all non-marine environments....
s and marsupial
Marsupial

Marsupials are an infraclass of mammals, characterized by a distinctive Pouch , in which females carry their young through early infancy....
s are not known to act as hosts.

The listing of host species among the reptiles has rarely been attempted. Ayala in 1978 listed 156 published accounts on 54 valid species and subspecies between 1909 and 1975. The regional breakdown was Africa
Africa

Africa is the world's second-largest and second most-populous continent, after Asia. At about 30.2 million km? including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area....
: 30 reports on 9 species; Australia
Australia

Australia, officially the Commonwealth of Australia, is a country in the southern hemisphere comprising the Australia of the world's smallest continent, the major island of Tasmania, and numerous list of islands of Australia in the Indian Ocean and Pacific Oceans....
, Asia
Asia

Asia is the world's largest and most populous continent. It covers 8.6% of the Earth's total surface area and, with over 4 billion people, it contains more than 60% of the world's current human population....
 & Oceania
Oceania

Oceania is a geography, often geopolitics, region consisting of numerous lands—mostly islands in the Pacific Ocean and vicinity. The term "Oceania" was coined in 1831 by French explorer Jules Dumont d'Urville....
: 12 reports on 6 species and 2 subspecies; Americas
Americas

The Americas are the region of the Western hemisphere that consists of the continents of North America and South America with their associated islands and regions....
: 116 reports on 37 species.

Because of the number of species parasited by ''Plasmodium'' further discussion has been broken down into following pages:



  • Plasmodium species infecting mammals other than primates
    Plasmodium species infecting mammals other than primates

    The subgenus Vinckeia of Plasmodium was created by Garnham to accommodate the mammalian parasites other than those infecting primates. Species infecting lemurs have also been included in this subgenus....


  • Plasmodium species infecting birds
    Plasmodium species infecting birds

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


  • Plasmodium species infecting reptiles
    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....


Species reclassified into other genera


The literature is replete with species initially classified as ''Plasmodium'' that have been subsequently reclassified. With DNA taxonomy some of these may be once again be classified as ''Plasmodium''. Some of these species are listed here for completeness.

The following species are currently (2007) regarded as belonging to the genus ''Hepatocystis'' rather than ''Plasmodium'':

  • ''Plasmodium epomophori''
  • ''Plasmodium kochi''
  • ''Plasmodium limnotragi'' Van Denberghe 1937
  • ''Plasmodium pteropi'' Breinl 1911
  • ''Plasmodium ratufae'' Donavan 1920
  • ''Plasmodium vassali'' Laveran 1905


The following species are now considered to belong to the genus ''Haemoemba'' rather than to ''Plasmodium'':

  • ''Plasmodium praecox''
  • ''Plasmodium rousseleti''


The following species been reclassified as a species of ''Garnia'':

  • ''Plasmodium gonatodi''


Host note: ''Hepatocystis epomophori'' infects the bat
Bat

Bats are mammals in the order Chiroptera. The forelimbs of all bats are developed as wings, making them the only mammals naturally capable of sustained flight ....
 (''Hypsignathus monstruosus'')

Species of dubious validity


The following species are currently regarded as questionable validity (''nomen dubium''). While most of these 'species' have been reported in the literature it has in general been difficult to independently confirm their existence. Some of these may be reclassified into different taxa while others seem likely to be declared to be non species i.e. that a mistake was made by the authors. However until a ruling on these species is made their status is likely to remain unclear.

  • ''Plasmodium bitis''
  • ''Plasmodium bowiei''
  • ''Plasmodium brucei''
  • ''Plasmodium bufoni''
  • ''Plasmodium caprea''
  • ''Plasmodium carinii''
  • ''Plasmodium causi''
  • ''Plasmodium chalcidi''
  • ''Plasmodium danilweskyi''
  • ''Plasmodium divergens''
  • ''Plasmodium effusum''
  • ''Plasmodium fabesia''
  • ''Plasmodium gambeli''
  • ''Plasmodium herodiadis''
  • ''Plasmodium lagopi
    Plasmodium lagopi

    Plasmodium lagopi is a parasite of the genus Plasmodium.Like all Plasmodium species P. lagopi has both vertebrate and insect hosts....
    ''
  • ''Plasmodium limnotragi''
  • ''Plasmodium malariae raupachi''
  • ''Plasmodium struthionis''


Further reading


Standard reference books for the identification of ''Plasmodium'' species

This book is the standard reference work on malarial species classification even if it a little dated now. A number of additional species have been described since its publication.

Other useful references

External links

Some history of malaria - http://muse.jhu.edu/journals/bulletin_of_the_history_of_medicine/v079/79.2slater.html