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Theileria

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Datasheet

Theileria

Summary

  • Last modified
  • 22 November 2019
  • Datasheet Type(s)
  • Invasive Species
  • Preferred Scientific Name
  • Theileria
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Protista
  •     Phylum: Protozoa
  •       Subphylum: Apicomplexa
  •         Order: Piroplasmorida

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PictureTitleCaptionCopyright
The life cycle of a typical Theileria species, as illustrated by those of T. annulata and T. parva, comprises a cycle of clonal replication of schizonts in mononuclear cells in lymphoid and reticuloendothelial tissues followed by the appearance of 'piroplasms' - small (<3u) and plemorphic organisms - in erythrocytes.  T.parva  proliferates as schizonts; its piroplasms do not multiply.  Schizonts are the major proliferating stage of T. annulata..  In infections of T. annulata, at least, elevated parasitaemias arise when erythrocytes are invaded by massive numbers of merozoites produced by large populations of schizonts. Members of the  T. orientalis/T. buffeli  group proliferates mainly as piroplasms. In every species, piroplasms include parasites undergoing gametogony and producing the gametocytes which are infective for ticks. Differentiation into gametes and sexual recombination occurs in the tick gut. Kinetes developing from zygotes in the gut cells appear to migrate directly to the
TitleLife cycle of a typical Theileria species
CaptionThe life cycle of a typical Theileria species, as illustrated by those of T. annulata and T. parva, comprises a cycle of clonal replication of schizonts in mononuclear cells in lymphoid and reticuloendothelial tissues followed by the appearance of 'piroplasms' - small (<3u) and plemorphic organisms - in erythrocytes. T.parva proliferates as schizonts; its piroplasms do not multiply. Schizonts are the major proliferating stage of T. annulata.. In infections of T. annulata, at least, elevated parasitaemias arise when erythrocytes are invaded by massive numbers of merozoites produced by large populations of schizonts. Members of the T. orientalis/T. buffeli group proliferates mainly as piroplasms. In every species, piroplasms include parasites undergoing gametogony and producing the gametocytes which are infective for ticks. Differentiation into gametes and sexual recombination occurs in the tick gut. Kinetes developing from zygotes in the gut cells appear to migrate directly to the
CopyrightElsevier Science
The life cycle of a typical Theileria species, as illustrated by those of T. annulata and T. parva, comprises a cycle of clonal replication of schizonts in mononuclear cells in lymphoid and reticuloendothelial tissues followed by the appearance of 'piroplasms' - small (<3u) and plemorphic organisms - in erythrocytes.  T.parva  proliferates as schizonts; its piroplasms do not multiply.  Schizonts are the major proliferating stage of T. annulata..  In infections of T. annulata, at least, elevated parasitaemias arise when erythrocytes are invaded by massive numbers of merozoites produced by large populations of schizonts. Members of the  T. orientalis/T. buffeli  group proliferates mainly as piroplasms. In every species, piroplasms include parasites undergoing gametogony and producing the gametocytes which are infective for ticks. Differentiation into gametes and sexual recombination occurs in the tick gut. Kinetes developing from zygotes in the gut cells appear to migrate directly to the
Life cycle of a typical Theileria speciesThe life cycle of a typical Theileria species, as illustrated by those of T. annulata and T. parva, comprises a cycle of clonal replication of schizonts in mononuclear cells in lymphoid and reticuloendothelial tissues followed by the appearance of 'piroplasms' - small (<3u) and plemorphic organisms - in erythrocytes. T.parva proliferates as schizonts; its piroplasms do not multiply. Schizonts are the major proliferating stage of T. annulata.. In infections of T. annulata, at least, elevated parasitaemias arise when erythrocytes are invaded by massive numbers of merozoites produced by large populations of schizonts. Members of the T. orientalis/T. buffeli group proliferates mainly as piroplasms. In every species, piroplasms include parasites undergoing gametogony and producing the gametocytes which are infective for ticks. Differentiation into gametes and sexual recombination occurs in the tick gut. Kinetes developing from zygotes in the gut cells appear to migrate directly to theElsevier Science
The role of three-host ticks in the transmission of Theileria spp. and Babesia spp.
TitleThree-host tick life history
CaptionThe role of three-host ticks in the transmission of Theileria spp. and Babesia spp.
CopyrightModified with permission of Elsevier Science
The role of three-host ticks in the transmission of Theileria spp. and Babesia spp.
Three-host tick life historyThe role of three-host ticks in the transmission of Theileria spp. and Babesia spp.Modified with permission of Elsevier Science
'Exotic' European Holstein-Friesian cows on a small holder farm in Asia Minor (Central Turkey).
TitleTypical host
Caption'Exotic' European Holstein-Friesian cows on a small holder farm in Asia Minor (Central Turkey).
CopyrightThe University of Edinburgh
'Exotic' European Holstein-Friesian cows on a small holder farm in Asia Minor (Central Turkey).
Typical host'Exotic' European Holstein-Friesian cows on a small holder farm in Asia Minor (Central Turkey). The University of Edinburgh
Diagrammatic representation of the intra-erythrocytic stages of T. annulata, T. parva and members of the T. orientalis/T. buffeli group. Some forms of piroplasms dominate in certain species: round and oval forms in T annulata; rods in T. parva; rods and elongate forms in T. orientalis/T. buffeli. Veils consist of a haemoglobin derived substance; bars are connected with the parasite and the outside of the cell. Both structures are thought to be of parasite origin. T. parva only produces a veil in Syncerus cafffer. Bars occur in all strains of T. orientalis/T. buffeli; veils are absent in N. American strains and not yet recorded for Chinese or African strains.
TitleDiagram
CaptionDiagrammatic representation of the intra-erythrocytic stages of T. annulata, T. parva and members of the T. orientalis/T. buffeli group. Some forms of piroplasms dominate in certain species: round and oval forms in T annulata; rods in T. parva; rods and elongate forms in T. orientalis/T. buffeli. Veils consist of a haemoglobin derived substance; bars are connected with the parasite and the outside of the cell. Both structures are thought to be of parasite origin. T. parva only produces a veil in Syncerus cafffer. Bars occur in all strains of T. orientalis/T. buffeli; veils are absent in N. American strains and not yet recorded for Chinese or African strains.
CopyrightUsed with permission from Academic Press Ltd.
Diagrammatic representation of the intra-erythrocytic stages of T. annulata, T. parva and members of the T. orientalis/T. buffeli group. Some forms of piroplasms dominate in certain species: round and oval forms in T annulata; rods in T. parva; rods and elongate forms in T. orientalis/T. buffeli. Veils consist of a haemoglobin derived substance; bars are connected with the parasite and the outside of the cell. Both structures are thought to be of parasite origin. T. parva only produces a veil in Syncerus cafffer. Bars occur in all strains of T. orientalis/T. buffeli; veils are absent in N. American strains and not yet recorded for Chinese or African strains.
Diagram Diagrammatic representation of the intra-erythrocytic stages of T. annulata, T. parva and members of the T. orientalis/T. buffeli group. Some forms of piroplasms dominate in certain species: round and oval forms in T annulata; rods in T. parva; rods and elongate forms in T. orientalis/T. buffeli. Veils consist of a haemoglobin derived substance; bars are connected with the parasite and the outside of the cell. Both structures are thought to be of parasite origin. T. parva only produces a veil in Syncerus cafffer. Bars occur in all strains of T. orientalis/T. buffeli; veils are absent in N. American strains and not yet recorded for Chinese or African strains.Used with permission from Academic Press Ltd.
Merozoites of Theileria equi: a free merozoite and a merozoite entering an erythrocyte (Note scale)
TitleUltrastructure of Theileria species
CaptionMerozoites of Theileria equi: a free merozoite and a merozoite entering an erythrocyte (Note scale)
CopyrightProf. H. Mehlhorn
Merozoites of Theileria equi: a free merozoite and a merozoite entering an erythrocyte (Note scale)
Ultrastructure of Theileria speciesMerozoites of Theileria equi: a free merozoite and a merozoite entering an erythrocyte (Note scale) Prof. H. Mehlhorn
Metaphase stage in the division of Theileria-infected cells, with theilerial body.
TitlePathogens
CaptionMetaphase stage in the division of Theileria-infected cells, with theilerial body.
CopyrightModified by permission of Nature
Metaphase stage in the division of Theileria-infected cells, with theilerial body.
PathogensMetaphase stage in the division of Theileria-infected cells, with theilerial body. Modified by permission of Nature
Telophase stage in the division of Theileria-infected cells, with no strand.
TitlePathogens
CaptionTelophase stage in the division of Theileria-infected cells, with no strand.
CopyrightModified by permission of Nature
Telophase stage in the division of Theileria-infected cells, with no strand.
PathogensTelophase stage in the division of Theileria-infected cells, with no strand. Modified by permission of Nature
Taurine cow infected with T. annulata showing debilitated condition.
TitleCow with Theileriosis (Theileria annulata)
CaptionTaurine cow infected with T. annulata showing debilitated condition.
CopyrightThe University of Edinburgh
Taurine cow infected with T. annulata showing debilitated condition.
Cow with Theileriosis (Theileria annulata)Taurine cow infected with T. annulata showing debilitated condition.The University of Edinburgh
Telophase, with theilerial body separating into two.
TitlePathogens
CaptionTelophase, with theilerial body separating into two.
CopyrightModified by permission of Nature
Telophase, with theilerial body separating into two.
PathogensTelophase, with theilerial body separating into two.Modified by permission of Nature
Reconstruction, both daughter cells with theilerial body.
TitlePathogens
CaptionReconstruction, both daughter cells with theilerial body.
CopyrightModified by permission of Nature
Reconstruction, both daughter cells with theilerial body.
PathogensReconstruction, both daughter cells with theilerial body.Modified by permission of Nature

Identity

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Preferred Scientific Name

  • Theileria

Taxonomic Tree

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  • Domain: Eukaryota
  •     Kingdom: Protista
  •         Phylum: Protozoa
  •             Subphylum: Apicomplexa
  •                 Order: Piroplasmorida
  •                     Family: Theileriidae
  •                         Genus: Theileria

Pathogen Characteristics

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Shared features of the life cycle and morphology of Theileria species

The life cycle and morphology of Theileria annulata and T. parva in their vertebrate hosts has been reviewed by Mehlhorn et al. (1994). After invading mononuclear cells, the sporozoites develop via trophozoites into multinucleate schizonts. This process is associated with activation of the host cell, which starts to proliferate, and at each cell division the parasite divides in synchrony with the transformed host cells (Hulliger et al., 1964). The infection is disseminated throughout the lymphoid tissues, by clonal expansion and metastasis of the schizont-infected cells. The schizonts then differentiate into merozoites. The mechanisms responsible for differentiation have been reviewed by Shiels et al. (1999, 2000). Released from the host cells, the merozoites enter the erythrocytes and, as intra-erythrocytic piroplasms, become available to ticks. The ultrastructure of the life cycle in their vertebrate hosts has been described and reviewed (Schein et al., 1978; Jura et al., 1983a, b; Mehlhorn and Schein, 1984; Shaw et al., 1991; Mehlhorn et al., 1994). Development and sexual recombination in ticks has been described for T. annulata (Schein et al., 1975; Voreb'eva, 1992) and for T. parva (Fawcett et al., 1982a, b).

Genetic diversity and relationships of Theileria species

The taxonomic relationships of the members of the order Piroplasmida have been controversial ever since they were discovered (Neitz, 1957; Markov, 1962; Krylov, 1978; Uilenberg, 1981; Norval et al., 1992). The species were first defined according to their morphology, hosts, tick vectors, distribution, antigenic relationships and ability/inability to cross-protect against other organisms. Molecular tools are now being used to confirm their identities and distributions, and to characterize their biological properties and host-parasite interactions (Allsopp et al., 1993; Morzaria et al., 1999; Sparagano, 1999; Sparagano and Jongejan, 1999). Molecular systematics have identified two monophyletic groups of Theileria: one group includes T. annulata, T. parva and T. lestoquardi [T. hirci]; the other group includes the members of the ‘T. orientalis/T. buffeli/T. sergenti' group and a new pathogen of small ruminants from China (Schnittger et al., 2000). 

T. annulata has proved to be genetically diverse, both within regions and across its endemic range (Melrose et al., 1984; Ben Miled et al., 1994; Katzer et al., 1998; Gubbels et al., 2000a), as have the different stocks of T. parva isolated from cattle and buffalo (Conrad et al., 1987, 1989; Allsopp et al., 1993). However, the different stocks of T. annulata are generally accepted to represent one species, and sub-speciation of members of the T. parva complex into T. parva parva, T. p. bovis and T. p. lawrencei is also not justified (Anon, 1989; Allsopp et al., 1993; Lawrence et al., 1994).

The widespread members of the T. orientalis/T. buffeli/T. sergenti group are also genetically diverse (Matsuba et al., 1992; Chae et al., 1998; Kim et al., 1998; Chansiri et al., 1999; Kawazu et al., 1999; Gubbels, 2000b) and their relationships difficult to resolve. Many cattle are infected with mixed populations of geographically variable parasites and, as well as those parasites already described as T. orientalis, T. sergenti and T. buffeli, other as yet undefined species probably exist in East Asia (Kim et al., 1998). T. sergenti is an invalid name according to Uilenberg (1981). Some authors propose retaining the name T. buffeli for parasites of the Asian buffalo, until the two species are shown to be identical. They suggest using the name T. orientalis for cattle parasites and creating two subspecies to distinguish the Japanese, Ikeda stock (T. o. sergenti) from all other members of the species (T. o. orientalis) (Kawazu et al., 1999). Others would prefer to call all members of this group T. buffeli, until individual 'species' can be defined, as they may all have originated from a group of buffalo parasites, and the name T. buffeli takes precedence over T. orientalis (Stewart et al., 1996; Gubbels et al., 2000a). In contrast to both these views, OIE (2013) says that there are two species: T. sergenti (occuring in the Far East) and T. buffeli/T. orientalis (with a global distribution).

A number of other species exist, but most are not major pathogens.

Distribution

For information on geographical distribution, see the datasheet on the disease theileriosis.

Further information

See the datasheets on Theileria annulata infections, Theileria orientalis/Theileria buffeli infections, Theileria parva infections, bovine theilerioses, and some of those on individual Theileria species.

Host Animals

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Animal nameContextLife stageSystem
Bos grunniens (yaks)Domesticated host
Bos indicus (zebu)Domesticated host
Bos taurus (cattle)Domesticated host
Bubalus bubalis (Asian water buffalo)Domesticated host
Capra hircus (goats)Domesticated host
Ovis aries (sheep)Domesticated host
Syncerus cafferWild host

Vectors and Intermediate Hosts

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VectorSourceReferenceGroupDistribution
Haemaphysalis bancroftiTickAustralia
Haemaphysalis humerosaTickAustralia
Haemaphysalis longicornisTickNew Zealand
Haemaphysalis punctataTickUkraine
Haemaphysalis qinhaiensisTickQinghai
Hyalomma anatolicumTickUzbekistan
Hyalomma detritumTickSpain
Hyalomma dromedariiTickUzbekistan
Hyalomma marginatumTickSpain
Hyalomma scupenseTickSouthern Russia
Rhipicephalus appendiculatusTickZambia
Rhipicephalus duttoniTickCongo Democratic Republic
Rhipicephalus zambeziensisTickZimbabwe

References

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Allsopp BA; Baylis HA; Allsopp MTEP; Cavalier-Smith T; Bishop RP; Carrington DM; Sohanpal B; Spooner P, 1993. Discrimination between six species of Theileria using oligonucleotide probes which detect small subunit ribosomal RNA sequences. Parasitology, 107(2):157-165; 36 ref.

Anon., 1989. Classification of Theileria parva reactions in cattle. In: Dolan TT, ed. Theileriosis in Eastern, Central and Southern Africa. Proceedings of a workshop on East Coast Fever Immunization. Lilongwe, Malawi. 20-22 September 1988. Nairobi, Kenya: International Laboratory for Research on Animal Diseases, 187-188.

Ben-Miled L; Dellagi K; Bernardi G; Melrose TR; Darghouth M; Bouattour A; Kinnaird J; Shiels B; Tait A; Brown CGD, 1994. Genomic and phenotypic diversity of Tunisian Theileria annulata isolates. Parasitology, 108(1):51-60; 29 ref.

Chae JoonSeok; Lee JooMook; Kwon OhDeog; Holman PJ; Waghela SD; Wagner GG, 1998. Nucleotide sequence heterogeneity in the small subunit ribosomal RNA gene variable (V4) region among and within geographic isolates of Theileria from cattle, elk and white-tailed deer. Veterinary Parasitology, 75(1):41-52; 40 ref.

Chansiri K; Kawazu SI; Kamio T; Terada Y; Fujisaki K; Philippe H; Sarataphan N, 1999. Molecular phylogenetic studies on Theileria parasites based on small subunit ribosomal RNA gene sequences. Veterinary Parasitology, 83(2):99-105; 23 ref.

Conrad PA; Iams K; Brown WC; Sohanpal B; Ole-MoiYoi OK, 1987. DNA probes detect genomic diversity in Theileria parva stocks. Molecular and Biochemical Parasitology, 25(3):213-226; 32 ref.

Conrad PA; Ole-Moiyoi OK; Baldwin CL; Dolan TT; O'Callaghan CJ; Njamunggeh REG; Grootenhuis JG; Stagg DA; Leitch BL; Young AS, 1989. Characterization of buffalo-derived theilerial parasites with monoclonal antibodies and DNA probes. Parasitology, 98(2):179-188; 23 ref.

Fawcett DW; Doxsey S; Buscher G, 1982. Salivary gland of the tick vector of East Coast fever. III. The ultrastructure of sporogony in Theileria parva. Tisue Cell, 14:183-206.

Fawcett DW; Doxsey S; Stagg DA; Young AS, 1982. The entry of sporozoites of Theileria parva into bovine lymphocytes in vitro. Electron microscopic observations. European Journal of Cell Biology, 27:10-21.

Gubbels M-J et al., 2000. Generation of a mosaic pattern of diversity in the major merozoite-piroplasm surface antigen of Theileria annulata. Molecular and Biochemical Parasitology, 110:23-32.

Gubbels M-J et al., 2000. Molecular characterization of the Theileria buffeli/orientalis group. International Journal for Parasitology, 30:943-952.

Hulliger L et al., 1964. Mode of multiplication of Theileria in cultures of bovine lymphocytic cells. Nature, 203:728-720.

Jura WGZO; Brown CGD; Kelly B, 1983. Fine structure and invasive behaviour of the early developmental stages of Theileria annulata in vitro. Veterinary Parasitology, 12:31-44.

Jura WGZO; Brown CGD; Rowlnd AC, 1983. Ultrastructural characteristics of in vitro parasite-lymphocyte behaviour in invasions with Theileria annulata and Theileria parva. Veterinary Parasitology, 12:115-134.

Katzer F et al., 1998. Phylogenetic analysis of Theileria and Babesia equi in relation to the establishment of parasite populations within novel host species and the development of diagnostic tests. Molecular and Biochemical Parasitology, 95:33-44.

Kawazu S et al., 1999. Phylogenetic relationships of the benign Theileria species in cattle and Asian buffalo based on the major piroplasm surface protein (p33/34) gene sequences. International Journal of Parasitology, 29:613-618.

Kim SamJu; Tsuji M; Kubota S; Wei Q; Lee JooMuk; Ishihara C; Onuma M, 1998. Sequence analysis of the major piroplasm surface protein gene of benign bovine Theileria parasites in East Asia. International Journal for Parasitology, 28(8):1219-1227; 24 ref.

Krylov MV, 1978. The origin of blood parasitism in Piroplasmida. Trudy-Zoologicheskogo-Instituta, Leningrad-Fauna-i-sistematika-odnokletochnykh-zhivotnykh, 78:6-15.

Lawrence JA; de Vos AJ; Irvin AD, 1994. Theileriosis. In: Coetzer JAW, Thomson GR, Tustin RC, Kriek NPJ, eds. Infectious diseases of livestock with special reference to South Africa. Volume 1. Oxford, UK: Oxford University Press, 307-308.

Markov AA, 1962. Les Theilerioses (Gonderioses). Bulletin de l'Office International des Epizooties, 58:165-193.

Matsuba T; Kawakami Y; Iwai H; Onuma M, 1992. Genomic analysis of Theileria sergenti stocks in Japan with DNA probes. Veterinary Parasitology, 41(1-2):35-43; 13 ref.

Mehlhorn H; Schein E, 1984. The piroplasms: life cycle and sexual stages. Advances in Parasitology. Volume 23., 37-103; 112 ref.

Mehlhorn H; Schein E; Ahmed JS, 1994. Theileria. In: Kreier JP, ed. Parasitic Protozoa, Volume 7. London, UK: Academic Press, 217-304.

Melrose TR; Brown CGD; Morzaria SP; Ocama JGR; Irvin AD, 1984. Glucose phosphate isomerase polymorphism in Theileria annulata and T. parva.. Tropical Animal Health and Production, 16(4):239-243; 19 ref.

Morzaria SP et al., 1999. Development of sero-diagnostic and molecular tools for the control of important tick-borne pathogens of cattle in Africa. Parassitologia, 41(Suppl. 1):73-80.

Neitz WO, 1957. Theileriosis, gonderiosis and cytauxzoonosis. A review. Onderstepoort Journal of Veterinary Research, 27:275-318.

Norval RAI; Perry BD; Young AS, 1992. The epidemiology of theileriosis in Africa. London, UK: Academic Press Limited, xiii + 481 pp.; 61 pp. of ref.

OIE (World Organisation for Animal Health), 2013. Manual of Diagnostic Tests and Vaccines for Terrestrial Animals. Paris, France: World Organisation for Animal Health. http://www.oie.int/en/international-standard-setting/terrestrial-manual/access-online/

Schein E; Buscher G; Friedhoff KT, 1975. On the life cycle of Theileria annulata (Dschunkowsky & Luhs 1904) in the midgut and haemolymph of Hyalomma anatolicum anatolicum (Koch 1884). Zeitschrift fur Parasitenkunde, 47:165-167.

Schein E; Mehlhorn H; Warnecke M, 1978. Electronmicroscopic studies on the schizogony of four Theileria species of cattle (T. parva, T. lawrencei, T. annulata and T. mutans). Protistologia, 14:337-348.

Schnittger L et al., 2000. Ribosomal small sub-unit RNA sequence analysis of Theileria lestoquardi and a Theileria species highly pathogenic for small ruminants in China. Parasitology Research, 86:352-358.

Shaw MK; Tilney LG; Musoke AJ, 1991. The entry of Theileria parva sporozoites in bovine lymphocytes. Evidence for MHCclass I involvement. Journal of Cellular Biology, 113:87-101.

Shiels B; Fox M; McKellar S; Kinnaird J; Swan D, 2000. An upstream element of the TamS1 gene is a site of DNA-protein interactions during differentiation to the merozoite. Journal of Cell Science, 113:2243-2252.

Shiels BR, 1999. Should I stay or should I go now? A stochastic model of stage differentiation in Theileria annulata. Parasitology Today, 15(6):241-245; 43 ref.

Sparagano O, 1999. Molecular diagnosis of Theileria and Babesia species. Journal of Veterinary Parasitology, 13:83-92.

Sparagano O; Jongejan F, 1999. Molecular characterization of ticks and tick-borne pathogens. Parassitologia, 41(Suppl. 1):101-105.

Stewart NP; Uilenberg G; Vos AJ de, 1996. Review of Australian species of Theileria, with special reference to Theileria buffeli of cattle. Tropical Animal Health and Production, 28(1):81-90; 63 ref.

Uilenberg G, 1981. Theilerial species of domestic stock. In: Irvin AD, Cunningham MP, Young AS, eds. Advances in the control of theileriosis. The Hague, Netherlands: Martinus Nijhoff Publishers, 4-38.

Vorob'eva EV, 1992. Peculiarities in the development of Theileria in the salivary glands of ticks of the genus Hyalomma. Parazitologicheskii Sbornik (Leningrad), 37:161-172; [2 plates (unpaged).]; 28 ref.

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