Difference between revisions of "Theileria"

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[[Image:Theileria parva life cycle.jpg|thumb|right|150px|''Theileria parva'' Life Cycle Diagram - Dennis Jacobs & Mark Fox RVC]]
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{{OpenPagesTop}}
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[[Image:Lymph node smear East Coast Fever.jpg|thumb|right|150px|Lymph node smear of a cow with East Coast Fever - Drs. Elizabeth Howerth and Bruce LeRoy, Department of Pathology, UGA College of Veterinary Medicine]]
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{{Taxobox
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[[Image:H and E stain brain East Coast Fever.jpg|thumb|right|150px|H and E stain of brain and meningal vessels of a cow with East Coast Fever - Drs. Elizabeth Howerth and Bruce LeRoy, Department of Pathology, UGA College of Veterinary Medicine]]
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|name              = ''Theileria'' spp
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[[Image:Theileria cervi.jpg|thumb|right|150px|''Theileria cervi'' (deer) - Drs. Elizabeth Howerth and Bruce LeRoy, Department of Pathology, UGA College of Veterinary Medicine]]#
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|kingdom            = Protista
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|sub-kingdom        =
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|phylum            = [[:Category:Protozoa|Protozoa]]
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|super-class        =
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|class              =
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|sub-class          =
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|super-order        =
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|order              = Piroplasmorida
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|sub-order          =
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|super-family      =
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|family            = Theileriidae
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|sub-family        =
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|genus              = Theileria
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|species            = ''Theileria parva'' and others
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}}
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==Introduction==
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[[Image:Theileria parva life cycle.jpg|thumb|right|300px|''Theileria parva'' Life Cycle Diagram - Dennis Jacobs & Mark Fox RVC]]
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[[File:Theileria_lifecycle.gif|thumb|200px|right|''Theileria'' Lifecycle]]
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''Theileria'' species are a group of '''[[Protozoa | protozoan]]''' pathogens causing severe '''lymphatic proliferative disease''' in cattle.
  
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*Main species of veterinary importance is ''Theileria parva''
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'''''T. parva''''' is the species of most veterinary importance, affecting cattle in Central and Eastern Africa and is the cause of [[East Coast Fever | East Coast Fever]].
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**Causes '''[[East Coast Fever]]'''
 
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***Severe, proliferative lymphatic disease of cattle
 
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***Central and Eastern Africa
 
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***Transmitted by [[Hard Ticks - Overseas|''Rhipicephalus appendiculatus'']]
 
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***[[Ticks#Disease Transmission|Trans-stadial]] transmission
 
  
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*Other ''Theileria'' species cause production losses in cattle and sheep in the Middle East, Mediterranean and in Northern Africa
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Other species cause significant economic losses in the Mediterranean, Middle East and Northern Africa.
  
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'''Life Cycle'''
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==Lifecycle==
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*Incubation phase lasts 1 week
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''Theileria'' are transmitted via the [[Haemaphysalis spp.|''Haemaphysalis'']] and [[Rhipicephalus spp.|''Rhipicephalus'']] species of '''[[Ticks|tick]] vectors'''.
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'''Sporozoites''' enter '''mononuclear''' cells of the host and develop into '''trophozoites''' and multinucleate '''schizonts''' by '''asexual''' reproduction. This process stimulates proliferation of the host cells, allowing further multiplication of the parasite. The local '''[[Lymph Nodes - Anatomy & Physiology|lymph nodes]]''' are first infected.
  
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*Lymphoblast proliferation
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Schizonts then '''disseminate''' through the '''[[:Category:Primary Lymphoid Tissue | lymphoid tissues]]''' before differentiating into '''merozoites'''.
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**Local [[Lymph Nodes - Anatomy & Physiology|lymph node]] first infected then spreads through body
 
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**Occurs in week two
 
  
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*Lymphoid depletion
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The merozoites enter the '''[[Erythrocytes | erythrocytes]]''' and form '''piroplasms''' which are '''infective to ticks''' and capable of sexual reproduction.
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**[[Lymphocytes - Introduction|Lymphocytes]] killed
 
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**Decreases lymphopoiesis
 
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**Occurs in week 3
 
  
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*Total incubation period takes about 18 days
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Sexual reproduction occurs within the nymph and larval stages of the [[Ticks |tick]] and the final infective stage is present within the '''salivary glands''' and is transmitted to mammalian hosts when bloodfeeding.
  
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'''Diagnosis'''
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Transmission in the tick is then '''[[Ticks#Disease Transmission|trans-stadial]]'''.
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*Clinical signs
 
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**Pyrexia
 
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**Enlarged local [[Lymph Nodes - Anatomy & Physiology|lymph node]]
 
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***Usually parotid [[Lymph Nodes - Anatomy & Physiology|lymph node]] as [[Hard Ticks - Overseas|''Rhipicephalus appendiculatus'']] feeds in the ear
 
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**Loss of condition
 
  
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*Examine Giemsa stained smears of:
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In endemic areas, '''endemic stability''' is often reached, in which most or all cattle may be infected and be carriers and most ticks are also infected, but young calves gain solid immunity from their immune dams and therefore rarely show clinical disease. This state however takes time to stabilise and will cause significant economic losses in the process.
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**Local [[Lymph Nodes - Anatomy & Physiology|lymph node]] aspirated for schizonts
 
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**Blood smears for piroplasms in red blood cells
 
  
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*Post-mortem
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For more information on ticks as vectors, see [[Tick Disease Transmission]].
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**Pulmonary oedema
 
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**Gut mucosal haemorrhages
 
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**[[Lymph Nodes - Anatomy & Physiology|Lymph node]] and [[Spleen - Anatomy & Physiology|splenic]] cellular atrophy
 
  
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'''Control'''
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==Pathogenesis==
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*Integrated control of both the [[Tick Control|tick vector]] and disease
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[[Lymphocytes - Introduction|Lymphocytes]] are '''killed''' by invading protozoa and later in disease, '''lymphopoeisis''' is reduced and prevented.
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**[[Vaccines|Vaccination]] and [[Ectoparasiticides]]
 
  
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*Current [[Vaccines|vaccination]] is live unattentuated
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==Diseases==
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**Contains frozen stabilate of ground up tick gut containing infective sporozoites
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<big><b>[[Theileriosis - Cattle |Bovine Theileriosis]]
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**Long lasting oxytetracycline administered at the same time to slow down schizogony giving the immune response time to develop
 
  
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[[East Coast Fever]]
  
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''Theileria equi'' (formerly ''Babesia equi'') and ''Babesia caballi'' cause [[Babesiosis - Horse|babesiosis in horses]]
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[[Babesiosis - Horse|Equine Babesiosis]]</b></big>
  
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[[Theileriosis - Cattle]]
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==''Theileria parva''==
  
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==Test yourself with the Piroplasmida Flashcards==
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''T. parva'' is primarily a parasite of '''African buffalo''' and the cause of '''[[Theileriosis - Cattle | Bovine Theileriosis]]''' and '''[[East Coast Fever]]'''. It may be transmitted by a wide range of [[Ticks |tick]] hosts although ''Rhipicephalus appeniculatus'' is the most importnat in the field.
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The protozoa form '''rod shaped''' piroplasms within host [[Erythrocytes | erythrocytes]].
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Sheep and mice can also be infected.
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==''Theileria annulata''==
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Also Known As: '''''T. dispar''
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''T. annulata'' is also a cause of [[Theileriosis - Cattle |Bovine Theileriosis]]. The parasite infects '''[[Macrophages |macrophages]]''' and '''[[B cells| B Lymphocytes]]''' forming '''round or oval''' piroplasma within host [[Erythrocytes | erythrocytes]].
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It also infects sheep and yaks.
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==''Theileria equi''==
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''Theileria equi'' (formerly ''Babesia equi'') and ''Babesia caballi'' cause [[Babesiosis - Horse|babesiosis in horses]].
 +
 
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{{Learning
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|flashcards = [[Piroplasmida_Flashcards|Piroplasmida Flashcards]]
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}}
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==References==
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<references/>
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{{CABI source
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|datasheet = [http://www.cabi.org/ahpc/?compid=3&dsid=96673&loadmodule=datasheet&page=2144&site=160 Theileria]
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|date = 4/06/2011
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}}
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<br><br><br>
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{{Nick Lyons
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|date = July 8, 2012}}
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==Webinars==
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<rss max="10" highlight="none">https://www.thewebinarvet.com/parasitology/webinars/feed</rss>
  
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[[Piroplasmida_Flashcards|Piroplasmida Flashcards]]
 
  
 
[[Category:Piroplasmida]]
 
[[Category:Piroplasmida]]
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[[Category:CABI Expert Review]][[Category:CABI AHPC Pages]]
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[[Category:To_Do_-_Steph]]
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[[Category:Nick Lyons reviewed]]

Latest revision as of 16:09, 3 January 2023


Theileria spp
Kingdom Protista
Phylum Protozoa
Order Piroplasmorida
Family Theileriidae
Genus Theileria
Species Theileria parva and others

Introduction

Theileria parva Life Cycle Diagram - Dennis Jacobs & Mark Fox RVC
Theileria Lifecycle

Theileria species are a group of protozoan pathogens causing severe lymphatic proliferative disease in cattle.

T. parva is the species of most veterinary importance, affecting cattle in Central and Eastern Africa and is the cause of East Coast Fever.

Other species cause significant economic losses in the Mediterranean, Middle East and Northern Africa.

Lifecycle

Theileria are transmitted via the Haemaphysalis and Rhipicephalus species of tick vectors.

Sporozoites enter mononuclear cells of the host and develop into trophozoites and multinucleate schizonts by asexual reproduction. This process stimulates proliferation of the host cells, allowing further multiplication of the parasite. The local lymph nodes are first infected.

Schizonts then disseminate through the lymphoid tissues before differentiating into merozoites.

The merozoites enter the erythrocytes and form piroplasms which are infective to ticks and capable of sexual reproduction.

Sexual reproduction occurs within the nymph and larval stages of the tick and the final infective stage is present within the salivary glands and is transmitted to mammalian hosts when bloodfeeding.

Transmission in the tick is then trans-stadial.

In endemic areas, endemic stability is often reached, in which most or all cattle may be infected and be carriers and most ticks are also infected, but young calves gain solid immunity from their immune dams and therefore rarely show clinical disease. This state however takes time to stabilise and will cause significant economic losses in the process.

For more information on ticks as vectors, see Tick Disease Transmission.

Pathogenesis

Lymphocytes are killed by invading protozoa and later in disease, lymphopoeisis is reduced and prevented.

Diseases

Bovine Theileriosis

East Coast Fever

Equine Babesiosis

Theileria parva

T. parva is primarily a parasite of African buffalo and the cause of Bovine Theileriosis and East Coast Fever. It may be transmitted by a wide range of tick hosts although Rhipicephalus appeniculatus is the most importnat in the field.

The protozoa form rod shaped piroplasms within host erythrocytes.

Sheep and mice can also be infected.

Theileria annulata

Also Known As: T. dispar

T. annulata is also a cause of Bovine Theileriosis. The parasite infects macrophages and B Lymphocytes forming round or oval piroplasma within host erythrocytes.

It also infects sheep and yaks.

Theileria equi

Theileria equi (formerly Babesia equi) and Babesia caballi cause babesiosis in horses.



Theileria Learning Resources
FlashcardsFlashcards logo.png
Flashcards
Test your knowledge using flashcard type questions 		Piroplasmida Flashcards


References


CABIlogo

This article was originally sourced from The Animal Health & Production Compendium (AHPC) published online by CABI during the OVAL Project.

The datasheet was accessed on 4/06/2011.

This article has been expert reviewed by Nick Lyons MA VetMB CertCHP MRCVS

Date reviewed: July 8, 2012


Webinars

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