''Lankesterella'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

in the

phylum In biology, a phylum (; plural: phyla) is a level of classification or taxonomic rank below kingdom and above class. Traditionally, in botany the term division has been used instead of phylum, although the International Code of Nomenclatu ...

Apicomplexa The Apicomplexa (also called Apicomplexia) are a large phylum of parasitic alveolates. Most of them possess a unique form of organelle that comprises a type of non-photosynthetic plastid called an apicoplast, and an apical complex structure. The ...

. Species in this genus infect amphibians, reptiles and

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

s. The type species is ''Lankesterella minima''.

History

This genus was created by Labbe in 1899. This genus is more commonly known as ''

Atoxoplasma ''Atoxoplasma'' is a genus of parasitic alveolates in the phylum Apicomplexa. The species in this genus infect birds. They are spread by the orofaecal route. History This genus was created by Garnham in 1950. The history of this genus has been ...

'', it is a genus of parasitic alveolates in the phylum Apicomplexa. Atoxoplasma species in passerines are a group of organisms with intestinal and extraintestinal forms that can cause significant morbidity and mortality but are not transmissible by syringe. These genera were united by Lainson in 1959. They were separated again by Levin in 1982. More commonly known as Atoxoplasma, it is a genus of parasitic alveolates in the phylum Apicomplexa. ''Apicomplexans'' are obligate intracellular parasites that typically invade blood cells. They have a distinct feature called the ''

apical complex The Apicomplexa (also called Apicomplexia) are a large phylum of parasitic alveolates. Most of them possess a unique form of organelle that comprises a type of non-photosynthetic plastid called an apicoplast, and an apical complex structure. The ...

'' which helps in the penetration of the parasite into the host cell. Atoxoplasma sp. in passerines is a group of organisms with intestinal and extraintestinal forms that can cause significant morbidity and mortality. This latter name was coined by Garnham in 1950 for a group of parasites resembling ''

Toxoplasma ''Toxoplasma gondii'' () is an obligate intracellular parasitic protozoan (specifically an apicomplexan) that causes toxoplasmosis. Found worldwide, ''T. gondii'' is capable of infecting virtually all warm-blooded animals, but felids, such as ...

''. Recent molecular studies revealed that some of the avian parasites which were initially thought to be ''

Hepatozoon ''Hepatozoon'' is a genus of Apicomplexa alveolates which incorporates over 300 species obligate intraerythrocytic parasites. Species have been described from all groups of tetrapod vertebrates, as well as a wide range of haematophagous arthropod ...

'' species were actually found to be closely related to the amphibian parasite ''Lankesterella minima''. The apicomplexan genera Lankesterella and Schellackia were largely believed to form a monophyletic clade within the family Lankesterellidae. However, phylogenetic analyses revealed they have an independent evolutionary origin. Morphological identification is clearly not enough due to the many errors that occur in identification and hence the need for

DNA barcoding DNA barcoding is a method of species identification using a short section of DNA from a specific gene or genes. The premise of DNA barcoding is that by comparison with a reference library of such DNA sections (also called " sequences"), an indi ...

for precise identification of the target species.

Description

''Lankesterella'' are extra-intestinal coccidia that invades the host blood. Criteria for the specific differentiation of ''Lankesterella'' are limited due to the fact that they are much similar in morphology with other ''apicomplexans'' such as ''

Isospora ''Isospora'' is a genus of internal parasites in the subclass Coccidia. It is responsible for the condition isosporiasis, which causes acute, non-bloody diarrhoea in immunocompromised individuals. Taxonomy At least 248 species were original ...

s'' and ''hepatazoons''. The most commonly described stages are the sporozoites found in the peripheral blood erythrocytes. Despite considerable structural divergences that have been observed among the sporozoite shapes, a system for taxonomic differentiation has not been developed. Descriptions of the stages developing in the viscera are less available as they require necropsy of the host. Lankesterella species are commonly known in amphibians and reptiles, but in recent times it has been found to also infect avian species. The

oocyst Apicomplexans, a group of intracellular parasites, have life cycle stages that allow them to survive the wide variety of environments they are exposed to during their complex life cycle. Each stage in the life cycle of an apicomplexan organis ...

s usually contain more than 32

sporozoite Apicomplexans, a group of intracellular parasites, have life cycle stages that allow them to survive the wide variety of environments they are exposed to during their complex life cycle. Each stage in the life cycle of an apicomplexan organism is ...

s. There are no sporocysts.

Life cycle

In the species that infect amphibians, the vectors are leeches. However, the lifecycle in avian species is still unknown since they have similar blood stages to other related apicomplexans such as

hepatozoon ''Hepatozoon'' is a genus of Apicomplexa alveolates which incorporates over 300 species obligate intraerythrocytic parasites. Species have been described from all groups of tetrapod vertebrates, as well as a wide range of haematophagous arthropod ...

s and

isospora ''Isospora'' is a genus of internal parasites in the subclass Coccidia. It is responsible for the condition isosporiasis, which causes acute, non-bloody diarrhoea in immunocompromised individuals. Taxonomy At least 248 species were original ...

s. The fact that ''Lankesterella'' and ''

Schellackia The genus ''Schellackia'' comprises obligate unicellular eukaryotic parasites within the phylum Apicomplexa, and infects numerous species of lizards and amphibians worldwide. ''Schellackia'' is transmitted via insect vectors, primarily mites an ...

'' is nested within the same paraphyletic ''

Eimeriidae Eimeriidae is a family of Apicomplexa. It contains the following genera: *'' Acroeimeria'' Paperna & Landsberg, 1989 *'' Alveocystis'' Bel'tenev, 1980 *'' Caryospora'' Léger, 1904 *''Cyclospora'' Schneider, 1881 *''Diaspora'' Léger, 1898 *''Dor ...

'' makes the lifecycle of these parasites to be considered as an evolutionary novelty. Transmission is by a blood-sucking vector that exerts a mechanical role in the transmission between hosts. The infective stages of the parasite remain completely dormant in the vectors without any development. Transmission in amphibians and reptiles occurs by blood-sucking arthropods such as leeches (intermediate hosts) or through the consumption of another definitive host (a snake eating an infected rat) and transmission is avian species is still unknown. This uncertainty is due to the fact that further investigations into the life cycle and the use of molecular tools for the identification of different species remain important in order to better understand the biology of the ''lankesterella'' species. (Smith, T.G., 1996)
/ref> The sporozoites invade macrophages or

endothelial cell The endothelium is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the rest of the ves ...

s. After development there, they invade circulating blood cells. The sporozoites may also invade

liver The liver is a major organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the synthesis of proteins and biochemicals necessary for digestion and growth. In humans, it ...

parenchyma or tissue macrophages. A quite distinct feature of the parasite is that it invades the

leukocyte White blood cells, also called leukocytes or leucocytes, are the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders. All white blood cells are produced and derived from mul ...

s in birds and

erythrocyte Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek ''erythros'' for "red" and ''kytos'' for "holl ...

s in amphibians and reptiles

Host records

Vertebrate

*''L. hylae'' - European gree tree frog ('' Hyla caerula'') *''L. minima'' - African common toad (''

Bufo regularis ''Sclerophrys regularis'', commonly known as the African common toad, square-marked toad, African toad, Egyptian toad, African bouncing toad (due to the bouncing motion) and Reuss's toad, is a species of toad in the family Bufonidae. It is found ...

''), cane toad (''

Bufo marinus The cane toad (''Rhinella marina''), also known as the giant neotropical toad or marine toad, is a large, terrestrial true toad native to South and mainland Central America, but which has been introduced to various islands throughout Ocea ...

''), blue tit (''

Cyanistes caeruleus The Eurasian blue tit (''Cyanistes caeruleus'') is a small passerine bird in the tit family, Paridae. It is easily recognisable by its blue and yellow plumage and small size. Eurasian blue tits, usually resident and non-migratory birds, are ...

''), rice field frogs (''

Hoplobatrachus rugulosus The Chinese edible frog, East Asian bullfrog, or Taiwanese frog (''Hoplobatrachus rugulosus'') is a species of frog in the family Dicroglossidae. It is found in Cambodia, China, Hong Kong, Laos, Macau, Malaysia, Myanmar, the Philippines, Taiwan, ...

''), frog (''

Rana esculenta The edible frog (''Pelophylax'' kl. ''esculentus'') is a species of common European frog, also known as the common water frog or green frog (however, this latter term is also used for the North American species '' Rana clamitans''). It is use ...

''), leopard frogs, (''

Rana pipiens ''Lithobates pipiens''Integrated Taxonomic Information System nternet2012''Lithobates pipiens'' pdated 2012 Sept; cited 2012 Dec 26Available from: www.itis.gov/ or ''Rana pipiens'', commonly known as the northern leopard frog, is a species of le ...

'') *''L. macrovacuolata'' - great tit (''

Parus major The great tit (''Parus major'') is a passerine bird in the tit family Paridae. It is a widespread and common species throughout Europe, the Middle East, Central Asia and east across the Palearctic to the Amur River, south to parts of North Af ...

'') *''L. vacuolata'' - common house martin (''

Delichon urbicum The common house martin (''Delichon urbicum''), sometimes called the northern house martin or, particularly in Europe, just house martin, is a migratory passerine bird of the swallow family which breeds in Europe, north Africa and across t ...

'') *''L. valsainensis'' - Eurasian blue tit(''

'') *''L. kabeeni'' - sedge warbler (''

Acrocephalus schoenobaenus The sedge warbler (''Acrocephalus schoenobaenus'') is an Old World warbler in the genus '' Acrocephalus''. It is a medium-sized warbler with a brown, streaked back and wings and a distinct pale supercilium. Sedge warblers are migratory, crossing ...

''), marsh warbler (''

Acrocephalus palustris The marsh warbler (''Acrocephalus palustris'') is an Old World warbler currently classified in the family Acrocephalidae. It breeds in temperate Europe and the western Palearctic and winters mainly in southeast Africa. It is notable for incorpo ...

'') *''L. poeppigii'' - frog ('' Bufo poeppigii'') *''L. tritonis'' - newt ('' Triton cristatus'') ;Parasite species unknown *White's tree frogs (''

Litoria caerulea The Australian green tree frog (''Ranoidea caerulea''), also known as simply green tree frog in Australia, White's tree frog, or dumpy tree frog, is a species of tree frog native to Australia and New Guinea, with introduced populations in th ...

'') *Oregon spotted frogs (''

Rana pretiosa The Oregon spotted frog (''Rana pretiosa'', meaning "precious frog") is a member of the frog family True frog, Ranidae of order Anura. It is a medium-sized aquatic frog endemic to the Pacific Northwest and historically well distributed in the Pug ...

'')

Vector

*''I. ricinus'' - tick (''

Ixodes ricinus ''Ixodes ricinus'', the castor bean tick, is a chiefly European species of hard-bodied tick. It may reach a length of when engorged with a blood meal, and can transmit both bacterial and viral pathogens such as the causative agents of Lyme dis ...

'') *''L. garnhami'' - mite (''

Dermanyssus gallinae ''Dermanyssus gallinae'' (also known as the red mite) is a haematophagous ectoparasite of poultry. It has been implicated as a vector of several major pathogenic diseases. Despite its common names, it has a wide range of hosts including sever ...

'') *''L. minima'' - leech ('' Hemiclepsis marginata'')

Synonyms

*''L. garnhami'' - ''L. serini'' *''L. kabeeni'' - ''L. vacuolata'',''L. macrovacuolata''

References

Apicomplexa genera {{Apicomplexa-stub