The Plasmodiumspecies infecting primates include the parasites causing malaria in humans.
The Plasmodiumspecies infecting primates include the parasites causing malaria in humans.
While infection of humans by other species is known, they are quite rare, in some instances, only a single case. In a number of the cases, the means of infection is unknown, and may be due to accident, i.e. infection by laboratory equipment or a bite by an animal. With the use of the polymerase chain reaction additional species have been and are still being identified that infect humans.
( Plasmodium brasilianum and Plasmodium rhodiani which have been reported to infect humans, are likely synonymous with P. malariae)
One possible experimental infection has been reported with Plasmodium eylesi . Fever and low grade parasitemia were apparent at 15 days. The volunteer (Dr Bennett) had previously been infected by Plasmodium cynomolgi and the infection was not transferable to a gibbon (P. eylesi 's natural host) so this cannot be regarded as definitive evidence of its ability to infect humans. A second case has been reported that may have been a case of P. eylesi but the author was not certain of the infecting species. [5]
A possible infection with Plasmodium tenue has been reported. [6] This report described a case of malaria in a three-year-old black girl from Georgia, United States, who had never been outside the US. She suffered from both P. falciparum and P. vivax malaria and while forms similar to those described for P. tenue were found in her blood even the author was skeptical about the validity of the diagnosis.
Confusingly Plasmodium tenue was proposed in the same year (1914) for a species found in birds. The human species is now considered to be likely to have been a misdiagnosis and the bird species is described on the Plasmodium tenue page.
Taxonomy in parasitology until the advent of DNA based methods has always been a problem and revisions in this area are continuing. A number of synonyms have been given for the species infecting humans that are no longer recognised as valid. [7] Since perusal of the older literature may be confusing some currently defunct species names are listed here.
P. causiasium
P. golgi
P. immaculatum
P. laverani var. tertium
P. laverani var. quartum
P. malariae var. immaculatum
P. malariae var. incolor
P. malariae var. irregularis
P. malariae var. parva
P. malariae var. quartanae
P. malariae var. quotidianae
P. perniciosum
P. pleurodyniae
P. praecox
P. quartana
P. quotidianum
P. sedecimanae
P. tenue
P. undecimanae
P. vegesio-tertaniae
Plasmodium shortii and Plasmodium osmaniae are now considered to be junior synonyms of Plasmodium inui.
Until recently the only known host of P. falciparum was humans but this species has also been described in gorillas ( Gorilla gorilla ) [8] and bonobos [9] There has been a single report of P. falciparum in a brown howler monkey ( Alouatta guariba ) and in black howler monkeys ( Alouatta caraya ) [10] but until this is confirmed its validity should be considered dubious.
A possible report of P. falciparum in a greater spot-nosed monkeys ( Cercopithecus nictitans ) has not been confirmed in a large survey. [11]
A species that clusters with P. falciparum and P. reichenowi has been identified in Gabon, Africa in chimpanzees ( Pan troglodytes ). [12] This appears to have diverged from these two species about 21 million years ago. It has only been identified from the sequence of its mitochondrion to date and further work is needed to characterise the species. A second report has confirmed the existence of this species in chimpanzees. [8] A third report has confirmed the existence of this species. [13]
Night monkeys ( Aotus nigriceps ) can be infected with P. falciparum. This infection may occur naturally. [14] Their potential role - if any - as a source of human infection is unknown.
Two additional species within the subgenus Laverania have been identified on the basis of DNA sequences alone: Plasmodium billbrayi and Plasmodium billcollinsi . [8] and bonobos [9] P. billbrayi was found in two subspecies of chimpanzee ( Pan troglodytes troglodytes and Pan troglodytes schweinfurthii ). P. billcollinsi was found in only one subspecies of chimpanzee (Pan troglodytes troglodytes). Further work is needed to characterise these species.
Humans are currently considered to be the only host for P. malariae. However Rodhain and Dellaert in the 1940s showed with transmission studies that P. malariae was present in chimpanzees. [15] [16] The presence of P. malaria in chimpanzees has been reported in Japan suggesting that this species may be able to act as a host. [17] A second paper has described the presence of P. malaria in wild chimpanzees. [13] Another paper has reported several cases of P. malariae in brown howler monkey ( Alouatta guariba ) and black howler monkeys ( Alouatta caraya ) [10] It has been shown that splectomised three-striped night monkey ( Aotus trivirgatus ) can be infected with P. malariae. [18] Another paper has confirmed the presence of P. malaria in chimpanzees. [19]
The existence of multiple independent reports seem to suggest that the chimpanzee and possibly other species may act as a host to P. malaria at least occasionally.
P. vivax will infect chimpanzees. Infection tends to be low grade but may be persistent and remain as source of parasites for humans for some time. P. vivax is also known to infect orangutans [20] and the brown howler monkey ( Alouatta guariba clamitans ) [10] P. vivax has been reported from chimpanzees living in the wild. [13] It has been suggested that vivax infection of the great apes in Africa may act as a reservoir given the prevalence of Duffy antigen negative humans in this area. [21]
Like P. vivax, P. ovale has been shown to be transmittable to chimpanzees. P. ovale has an unusual distribution pattern being found in Africa, Myanmar the Philippines and New Guinea. In spite of its admittedly poor transmission to chimpanzees given its discontigous spread, it is suspected that P. ovale may in fact be a zoonosis with an as yet unidentified host. If this is actually the case, the host seems likely to be a primate. A report has been published suggesting that P. ovale may be a natural parasite of chimpanzees [22] but this needs confirmation. P. ovale has since been described from chimpanzees living in the wild. [13] This suggests that human infection with this species may as previously suspected be a zoonosis.
It has been recently shown that P. ovale is actually two genetically distinct species that coexist. These species are Plasmodium ovale curtisi and Plasmodium ovale wallikeri. [23] These two species separated between 1.0 and 3.5 million years ago.
Plasmodium knowlesi has a natural reservoir in the macaques of Southeast Asia, and was only in 1965 identified as being transmissible to humans.
The remaining species capable of infecting humans all have other primate hosts.
Interrelatedness - The evolution of these species is still being worked out and the relationships given here should be regarded as tentative. This grouping, while originally made on morphological grounds, now has considerable support at the DNA level.
Many species of Plasmodium which infect primates have been divided into subspecies. Examples are listed below:
| Subspecies infecting primates |
|---|
*P. cynomolgi — P. cynomolgi bastianelli and P. cynomolgi ceylonensis.
|
 | This section lacks an overview of its topic.(March 2014) |
Most if not all Plasmodium species infect more than one host: the host records shown here should be regarded as incomplete.
It has been proposed that the species P. gora and P. gorb should be renamed P. adleri and P. blacklocki respectively.
New World monkeys of the family Cebidae: P. brasilianum and P. simium
Old World monkeys of the family Cercopithecidae: P. coatneyi, P. cynomolgi, P. fieldi, P. fragile, P.gonderi, P. georgesi, P. inui, P. knowlesi, P. petersi, P. shortti and P. simiovale
Gibbons of the family Hylobatidae: P. eylesi, P. hylobati, P. jefferyi and P. youngi
Orangutans (Pongo): P. pitheci and P. silvaticum
Gorillas and chimpanzees: P. billcollini, P. billbrayii, P. falciparum, P. gabonensi, P. gora, P. gorb, P. reichenowi, P. rodhaini and P. schwetzi
| This section lacks an overview of its topic.(March 2014) |
This listing may be incomplete as the taxonomy of this genus is under revision.
North American
Central American
South American
North Eurasian
Mediterranean
Afro-Arabian
Afrotropical
Indo-Iranian
Indo-Chinese hills
Malaysian
Chinese
Australasian
| This section lacks an overview of its topic.(March 2014) |
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 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, continuing the life cycle.
Plasmodium falciparum is a unicellular protozoan parasite of humans, and 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. It is responsible for around 50% of all malaria cases. P. falciparum is therefore regarded as the deadliest parasite in humans. It is also associated with the development of blood cancer and is classified as a Group 2A (probable) carcinogen.
Recrudescence is the recurrence of an undesirable condition. In medicine, it is usually defined as the recurrence of symptoms after a period of remission or quiescence, in which sense it can sometimes be synonymous with relapse. In a narrower sense, it can also be such a recurrence with higher severity than before the remission. "Relapse" conventionally has a specific meaning when used in relation to malaria.
Plasmodium vivax is a protozoal parasite and a human pathogen. This parasite is the most frequent and widely distributed cause of recurring malaria. Although it is less virulent than Plasmodium falciparum, the deadliest of the five human malaria parasites, P. vivax malaria infections can lead to severe disease and death, often due to splenomegaly. P. vivax is carried by the female Anopheles mosquito; the males do not bite.
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.
Plasmodium malariae is a parasitic protozoan that causes malaria in humans. It is one of several species of Plasmodium parasites that infect other organisms as pathogens, also including Plasmodium falciparum and Plasmodium vivax, responsible for most malarial infection. Found worldwide, it causes a so-called "benign malaria", not nearly as dangerous as that produced by P. falciparum or P. vivax. The signs include fevers that recur at approximately three-day intervals – a quartan fever or quartan malaria – longer than the two-day (tertian) intervals of the other malarial parasite.
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.
The Anopheles latens mosquito is an important vector for the transmission of malaria in humans and monkeys in Southeast Asia. It is an important vector for the transmission of human malaria in Sarawak; but because it is attracted to both humans and to macaques it is also responsible for the transmission of simian malarias to humans.
Laverania is a subgenus of the parasite genus Plasmodium. Infection with these species results in malaria. The subgenus was first described in 1958.
Malaria antigen detection tests are a group of commercially available rapid diagnostic tests of the rapid antigen test type that allow quick diagnosis of malaria by people who are not otherwise skilled in traditional laboratory techniques for diagnosing malaria or in situations where such equipment is not available. There are currently over 20 such tests commercially available. The first malaria antigen suitable as target for such a test was a soluble glycolytic enzyme Glutamate dehydrogenase. None of the rapid tests are currently as sensitive as a thick blood film, nor as cheap. A major drawback in the use of all current dipstick methods is that the result is essentially qualitative. In many endemic areas of tropical Africa, however, the quantitative assessment of parasitaemia is important, as a large percentage of the population will test positive in any qualitative assay.
Plasmodium eylesi is a parasite of the genus Plasmodium subgenus Plasmodium.
The history of malaria extends from its prehistoric origin as a zoonotic disease in the primates of Africa through to the 21st century. A widespread and potentially lethal human infectious disease, at its peak malaria infested every continent except Antarctica. Its prevention and treatment have been targeted in science and medicine for hundreds of years. Since the discovery of the Plasmodium parasites which cause it, research attention has focused on their biology as well as that of the mosquitoes which transmit the parasites.
Plasmodium fieldi is a parasite of the genus Plasmodium sub genus Plasmodium found in Malaysia. This species is related to Plasmodium ovale and Plasmodium simiovale. As in all Plasmodium species, P. fieldi has both vertebrate and insect hosts. The vertebrate hosts for this parasite are primates.
Plasmodium inui is a species of parasite, one of the species of simian Plasmodium that cause malaria in Old World monkeys.
Plasmodium schwetzi is a parasite of the genus Plasmodium subgenus Plasmodium.
Plasmodium coatneyi is a parasitic species that is an agent of malaria in nonhuman primates. P. coatneyi occurs in Southeast Asia. The natural host of this species is the rhesus macaque and crab-eating macaque, but there has been no evidence that zoonosis of P. coatneyi can occur through its vector, the female Anopheles mosquito.
Plasmodium cynomolgi is an apicomplexan parasite that infects mosquitoes and Asian Old World monkeys. In recent years, a number of natural infections of humans have also been documented. This species has been used as a model for human Plasmodium vivax because Plasmodium cynomolgi shares the same life cycle and some important biological features with P. vivax.
Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is a family of proteins present on the membrane surface of red blood cells that are infected by the malarial parasite Plasmodium falciparum. PfEMP1 is synthesized during the parasite's blood stage inside the RBC, during which the clinical symptoms of falciparum malaria are manifested. Acting as both an antigen and adhesion protein, it is thought to play a key role in the high level of virulence associated with P. falciparum. It was discovered in 1984 when it was reported that infected RBCs had unusually large-sized cell membrane proteins, and these proteins had antibody-binding (antigenic) properties. An elusive protein, its chemical structure and molecular properties were revealed only after a decade, in 1995. It is now established that there is not one but a large family of PfEMP1 proteins, genetically regulated (encoded) by a group of about 60 genes called var. Each P. falciparum is able to switch on and off specific var genes to produce a functionally different protein, thereby evading the host's immune system. RBCs carrying PfEMP1 on their surface stick to endothelial cells, which facilitates further binding with uninfected RBCs, ultimately helping the parasite to both spread to other RBCs as well as bringing about the fatal symptoms of P. falciparum malaria.
Plasmodium gaboni is a parasite of the genus Plasmodium subgenus Laverania.
{{cite journal}}: CS1 maint: multiple names: authors list (link){{cite journal}}: CS1 maint: multiple names: authors list (link){{cite journal}}: CS1 maint: multiple names: authors list (link){{cite journal}}: CS1 maint: multiple names: authors list (link){{cite journal}}: CS1 maint: multiple names: authors list (link){{cite journal}}: CS1 maint: multiple names: authors list (link){{cite journal}}: CS1 maint: multiple names: authors list (link) 
{{cite journal}}: CS1 maint: multiple names: authors list (link){{cite journal}}: CS1 maint: multiple names: authors list (link){{cite journal}}: CS1 maint: multiple names: authors list (link){{cite journal}}: CS1 maint: multiple names: authors list (link)