Theileria Explained

Theileria is a genus of parasites that belongs to the phylum Apicomplexa, and is closely related to Plasmodium. Two Theileria species, T. annulata and T. parva, are important cattle parasites.[1] T. annulata causes tropical theileriosis and T. parva causes East Coast fever. Theileria species are transmitted by ticks.[2] The genomes of T. orientalis Shintoku, Theileria equi WA,[3] Theileria annulata Ankara[4] and Theileria parva Muguga[5] have been sequenced and published.

Theileria equi is a known cause of equine piroplasmosis.[6]

Vaccines against Theileria are in development.[1] [7] In May 2010, a vaccine that was reported to protect cattle against East Coast fever had been approved and registered by the governments of Kenya, Malawi, and Tanzania.[8]

Description

Species in this genus undergo exoerythrocytic merogony in the lymphocytes, histiocytes, erythroblasts, and other cells of the internal organs. This is followed by invasion of the erythrocytes by the merozoites, which may or may not reproduce. When merogony does occur, no more than four daughter cells are produced. The frequent occurrence of elongated bacillary or "bayonet" forms within the erythrocyte is considered as characteristic of this genus.

The organism is transmitted by various tick species, including Rhipicephalus, Dermacentor, and Haemaphysalis. The organism reproduces in the tick as it progresses through its life stages.[9] Both T. annulata and T. parva induce transformation of infected cells of lymphocyte or macrophage/monocyte lineages. T. orientalis does not induce uncontrolled proliferation of infected leukocytes and instead multiplies predominantly within infected erythrocytes.

Genomics

The genomes of T. orientalis Shintoku[10] , Theileria equi WA, Theileria annulata Ankara and Theileria parva Muguga have been sequenced. Genomic data can be accessed PiroplasmaDB which is part of the Eukaryotic Pathogen Bioinformatic Resource (EuPathDB).[11]

Evolution

The genus is thought to have first appeared in ruminants during the Miocene. It is named for Gertrud Theiler, daughter of Arnold Theiler.

Transmission

Theileria spp. can be transmitted to cattle through tick bites, including the brown ear tick, a Rhipicephalus sp.

Important species

Treatment

External links

Notes and References

  1. Morrison W, McKeever D . 2006 . Current status of vaccine development against Theileria parasites . Parasitology . 133 . S169–87 . 17274845 . 10.1017/S0031182006001867. 928055 .
  2. 19273257 . Jan 2009 . Piroplasmids and ticks: a long-lasting intimate relationship . 14 . L.. Florin-Christensen . Schnittger . 14. 3064–3073 . 1093-9946 . Frontiers in Bioscience . M. . 10.2741/3435. free .
  3. Kappmeyer. Lowell S.. Thiagarajan. Mathangi. Herndon. David R.. Ramsay. Joshua D.. Caler. Elisabet. Djikeng. Appolinaire. Appolinaire Djikeng. Gillespie. Joseph J.. Lau. Audrey OT. Roalson. Eric H.. 2012-01-01. Comparative genomic analysis and phylogenetic position of Theileria equi. BMC Genomics. 13. 603. 10.1186/1471-2164-13-603. 3505731. 23137308 . free .
  4. Pain. Arnab. Renauld. Hubert. Berriman. Matthew. Murphy. Lee. Yeats. Corin A.. Weir. William. Kerhornou. Arnaud. Aslett. Martin. Bishop. Richard. 2005-07-01. Genome of the host-cell transforming parasite Theileria annulata compared with T. parva. Science . 309. 5731. 131–3. 10.1126/science.1110418 . 15994557. 34556923 .
  5. Gardner. Malcolm J.. Bishop. Richard. Shah. Trushar. de Villiers. Etienne P.. Carlton. Jane M.. Hall. Neil. Ren. Qinghu. Paulsen. Ian T.. Pain. Arnab. 2005-07-01. Genome sequence of Theileria parva, a bovine pathogen that transforms lymphocytes. Science . 309. 5731. 134–7. 10.1126/science.1110439 . 15994558. 37769438 .
  6. 16429803. 2003. Englund. L. P.. New diseases and increased risk of diseases in companion animals and horses due to transport. 100. 19–25. 0065-1699. Acta Veterinaria Scandinavica. Supplementum.
  7. A.. Review on the experience with live attenuated vaccines against tropical theileriosis in Tunisia: considerations for the present and implications for the future. 26. Vaccine. Suppl 6. G4–G10. Dec 2008 . 0264-410X. 19178892. Darghouth. 10.1016/j.vaccine.2008.09.065.
  8. Web site: Cattle disease vaccine launched 30 years after invention. 2010-05-07. SciDev.net (7 May 2010).
  9. Hayashida K, Hara Y, Abe T, Yamasaki C, Toyoda A, Kosuge T, Suzuki Y, Sato Y, Kawashima S, Katayama T, Wakaguri H, Inoue N, Homma K, Tada-Umezaki M, Yagi Y, Fujii Y, Habara T, Kanehisa M, Watanabe H, Ito K, Gojobori T, Sugawara H, Imanishi T, Weir W, Gardner M, Pain A, Shiels B, Hattori M, Nene V, Sugimoto C . Comparative genome analysis of three eukaryotic parasites with differing abilities to transform leukocytes reveals key mediators of Theileria-induced leukocyte transformation . mBio . 3 . 5 . e00204–12 . 2012 . 22951932 . 3445966 . 10.1128/mBio.00204-12 .
  10. Book: Harb. Omar S.. Roos. David S.. Parasite Genomics Protocols . The Eukaryotic Pathogen Databases: A Functional Genomic Resource Integrating Data from Human and Veterinary Parasites . 2015-01-01. 1201. 1–18. 10.1007/978-1-4939-1438-8_1 . 25388105. 6157018. Methods in Molecular Biology. 978-1-4939-1437-1.
  11. Mehlhorn . Heinz . Schein . Eberhard . Redescription of Babesia equi Laveran, 1901 as Theileria equi Mehlhorn, Schein 1998 . Parasitology Research . 1998 . 84 . 6 . 467–475 . 10.1007/s004360050431 . 9660136 . 27992280 . June 19, 2020.