Difference between revisions of "Tick-Borne Fever"

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===Tick-borne fever===
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{{OpenPagesTop}}
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Also Known As: '''''Pasture Fever''''' — '''''Tickborne Fever''''' — '''''Ruminant Anaplasmosis''''' — '''''TBF'''''
  
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*Caused by ''E. phagocytophila'' which has now been renamed as ''Anaplasma phagocytophilum''
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Caused By: '''''Anaplasma phagocytophilum''''', previously known as '''''Ehrlichia phagocytophila'''''
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*Affects ruminants in Europe
 
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*The tick ''Ixodes ricinis'' is the main vector
 
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*Animals remain carriers for up to 2 years, but are immune to reinfection
 
  
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*Clinical signs
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==Introduction==
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**Incubation period of 2 weeks; recovery in 2 weeks
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[[File:Anaplasmosis.jpg|thumb|200px|right|''Rickettsia'' spp. inside tick haemolymph cells. Sourced from Wikimedia Commons]]
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**Fever, anorexia, reduced growth rates in young animals
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[[File:Swollen tick-SteveFE.jpg|thumb|200px|right|''Ixodes'' tick. Sourced from Wikimedia commons]]
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**Reduced milk production, abortion, still birth
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Tick Borne Fever is a '''[[Rickettsiales |rickettsial]]''' disease affecting the '''[[Leucocytes |white blood cells]]''' of sheep and cattle, causing '''anaemia''' and seasonal “pasture fever”.
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**Leukopenia and thrombocytopenia
 
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**Causes immunosuppression in young lambs causing susceptibility to tick pyaemia and louping ill
 
  
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*Diagnosis
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Seasonal pasture fever occurs in cattle that are returned to tick infected pasture in the Spring.
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**Intracytoplasmic morulae in [[Neutrophils|neutrophils]] of Giemsa-stained blood smears during acute phase
 
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**Seroconversion detected by immunofluorescence
 
  
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*Treatment and control
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Human granulocytic ehrlichiosis, the '''zoonotic''' form of TBF is a potentially '''fatal''' disease reported in the UK, Europe and USA.
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**Oxtetracycline
 
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**Tick control
 
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**Prophylactic tetracyclines for lambs during first few weeks of life
 
  
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==Literature Search==
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==Signalment==
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[[File:CABI logo.jpg|left|90px]]
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TBF naturally affects primarily sheep and cattle, and less commonly, deer, horses and dogs.
  
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==Distribution==
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TBF has worldwide distribution including the UK. It is transmitted by '''''[[Ixodes spp. |Ixodes]]''''' ticks. Both adults and nymphs can transmit the disease. Transmission is '''[[Tick Disease Transmission |trans-stadial]].'''
  
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Use these links to find recent scientific publications via CAB Abstracts (log in required unless accessing from a subscribing organisation except for full text articles).
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==Clinical Signs==
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TBF causes '''multisystemic''' disease, causing cardiovascular, gastrointestinal, respiratory, reproductive and neurological signs, and also lymphadenopathy and wasting disease.
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'''Severe haematological changes''' including profound [[:Category:Anaemia|'''anaemia''']] and '''leucopaenia''' cause significant clinical signs.
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Initial [[lymphocytopaenia]] and '''prolonged [[neutropaenia]]''' are also features of TBF.
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A profound '''[[eosinophilia]]''' will occur for 17-20 days post-infection. <ref>Miert, A. S. J. P. A. Mvan., Duin, C. T. Mvan., Schotman, A. J. H., Franssen, F. F. (1984) '''Clinical, haematological and blood biochemical changes in goats after experimental infection with tick-borne fever. '''''Vet Parasitology, ''16(3/4):225-233; 29 </ref>
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Low serum Alkaline Phosphatase (ALP) and decreased zinc, iron and albumin are also common biochemical findings, along with high [[urea]], [[creatinine]] and [[bilirubin]].
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Recovered animals develop immunity but it is unknown how long this is effective for.
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==Diagnosis==
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Haematological and Biochemical changes as listed above along with '''marked pyrexia''' are highly suggestive, especially if historical findings are conducive.
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Demonstration of the '''organism''' in the '''[[Leucocytes |leucocytes]]''' in peripheral blood is confirmative.
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On '''post-mortem''' examination, the '''[[Spleen - Anatomy & Physiology|spleen]]''' is enlarged and mild liver damage is common. Lesions within the [[Lungs - Anatomy & Physiology|'''lung''']] are present and contain mononuclear infiltrate on histopathology. Thickening, ulceration and haemorrhage of the gastrointestinal tract become worse distally.
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The parasites may be visible within the neutrophils in sections of liver and lung.
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Antibodies can be detected using [[FAT|'''Indirect Immunofluorescence''' (IFAT)]], '''[[Complement Fixation]]''' and Immunoelectrophoresis (CIEP).
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==Treatment==
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''A. phagocytophilum'' is susceptible to '''oxytetracycline, sulphamethazine, sulphadimidine, doxycycline''' and '''trimethoprim-sulphonamides'''.
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==Control==
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[[Tick Control|Control of the tick vector ]]is expensive but effective.
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Use of [[Ectoparasiticides |ectoparasiticides]] and tick resistant breeds is also valuable.
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==Human Granulocytic Ehrlichiosis==
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Causes fever, malaise, headaches, sweats, nausea, confusion, anorexia, vomiting, weakness, diarrhoea, pneumonia, vertigo, seizures, GI bleeding and a skin rash.<ref>Bakken, J. S., Krueth, J., Tilden, R. L., Dumler, J. S., Kristiansen, B. E. (1996). '''Serological evidence of human granulocytic ehrlichiosis in Norway. '''''Eur J Clin Microbiol Inf Dis,'' 15(10):829-832; 12</ref>
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{{Learning
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|flashcards = [[Tick-Borne Fever 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=61126&loadmodule=datasheet&page=2144&site=160 tick-borne fever]
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|date = 6 June 2011
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}}
 
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[http://www.cabi.org/cabdirect/FullTextPDF/2009/20093115234.pdf ''' Tick-borne disease testing: canine erhlichiosis and anaplasmosis.''' Alleman, R.; The North American Veterinary Conference, Gainesville, USA, Small animal and exotics. Proceedings of the North American Veterinary Conference, Orlando, Florida, USA, 17-21 January, 2009, 2009, pp 629-631 - '''Full Text Article''']
 
  
  
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{{review}}
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{{OpenPages}}
  
 
[[Category:Rickettsiales]][[Category:Cattle Bacteria]][[Category:Sheep Bacteria]][[Category:Goat Bacteria]]
 
[[Category:Rickettsiales]][[Category:Cattle Bacteria]][[Category:Sheep Bacteria]][[Category:Goat Bacteria]]
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[[Category:To_Do_-_Bacteria]][[Category:To Do - Medium]]
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[[Category:Zoonoses]]
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[[Category:Cardiovascular Diseases - Cattle]][[Category:Respiratory Diseases - Cattle]][[Category:Alimentary Diseases - Cattle]][[Category:Reproductive Diseases - Cattle]][[Category:Neurological Diseases - Cattle]][[Category:Lymphoreticular and Haematopoietic Diseases - Cattle]]
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[[Category:Cardiovascular Diseases - Sheep]]
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[[Category:Respiratory Diseases - Sheep]]
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[[Category:Alimentary Diseases - Sheep]][[Category:Reproductive Diseases - Sheep]][[Category:Neurological Diseases - Sheep]]
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[[Category:Lymphoreticular and Haematopoietic Diseases - Sheep]]
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[[Category:CABI Expert Review]][[Category:CABI AHPC Pages]]
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[[Category:Nick L]]
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[[Category:Cardiology Section]]

Latest revision as of 17:30, 17 October 2013


Also Known As: Pasture Fever — Tickborne Fever — Ruminant Anaplasmosis — TBF

Caused By: Anaplasma phagocytophilum, previously known as Ehrlichia phagocytophila

Introduction

Rickettsia spp. inside tick haemolymph cells. Sourced from Wikimedia Commons
Ixodes tick. Sourced from Wikimedia commons

Tick Borne Fever is a rickettsial disease affecting the white blood cells of sheep and cattle, causing anaemia and seasonal “pasture fever”.

Seasonal pasture fever occurs in cattle that are returned to tick infected pasture in the Spring.

Human granulocytic ehrlichiosis, the zoonotic form of TBF is a potentially fatal disease reported in the UK, Europe and USA.

Signalment

TBF naturally affects primarily sheep and cattle, and less commonly, deer, horses and dogs.

Distribution

TBF has worldwide distribution including the UK. It is transmitted by Ixodes ticks. Both adults and nymphs can transmit the disease. Transmission is trans-stadial.

Clinical Signs

TBF causes multisystemic disease, causing cardiovascular, gastrointestinal, respiratory, reproductive and neurological signs, and also lymphadenopathy and wasting disease.

Severe haematological changes including profound anaemia and leucopaenia cause significant clinical signs.

Initial lymphocytopaenia and prolonged neutropaenia are also features of TBF.

A profound eosinophilia will occur for 17-20 days post-infection. [1]

Low serum Alkaline Phosphatase (ALP) and decreased zinc, iron and albumin are also common biochemical findings, along with high urea, creatinine and bilirubin.

Recovered animals develop immunity but it is unknown how long this is effective for.

Diagnosis

Haematological and Biochemical changes as listed above along with marked pyrexia are highly suggestive, especially if historical findings are conducive.

Demonstration of the organism in the leucocytes in peripheral blood is confirmative.

On post-mortem examination, the spleen is enlarged and mild liver damage is common. Lesions within the lung are present and contain mononuclear infiltrate on histopathology. Thickening, ulceration and haemorrhage of the gastrointestinal tract become worse distally.

The parasites may be visible within the neutrophils in sections of liver and lung.

Antibodies can be detected using Indirect Immunofluorescence (IFAT), Complement Fixation and Immunoelectrophoresis (CIEP).

Treatment

A. phagocytophilum is susceptible to oxytetracycline, sulphamethazine, sulphadimidine, doxycycline and trimethoprim-sulphonamides.

Control

Control of the tick vector is expensive but effective. Use of ectoparasiticides and tick resistant breeds is also valuable.

Human Granulocytic Ehrlichiosis

Causes fever, malaise, headaches, sweats, nausea, confusion, anorexia, vomiting, weakness, diarrhoea, pneumonia, vertigo, seizures, GI bleeding and a skin rash.[2]



Tick-Borne Fever Learning Resources
FlashcardsFlashcards logo.png
Flashcards
Test your knowledge using flashcard type questions 		Tick-Borne Fever Flashcards



References

  1. ↑ Miert, A. S. J. P. A. Mvan., Duin, C. T. Mvan., Schotman, A. J. H., Franssen, F. F. (1984) Clinical, haematological and blood biochemical changes in goats after experimental infection with tick-borne fever. Vet Parasitology, 16(3/4):225-233; 29
  2. ↑ Bakken, J. S., Krueth, J., Tilden, R. L., Dumler, J. S., Kristiansen, B. E. (1996). Serological evidence of human granulocytic ehrlichiosis in Norway. Eur J Clin Microbiol Inf Dis, 15(10):829-832; 12


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 6 June 2011.









 This article has been peer reviewed but is awaiting expert review. If you would like to help with this, please see more information about expert reviewing.



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