Difference between revisions of "Tick-Borne Fever"

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===Tick-borne fever===
Also Known As: '''''Pasture Fever''''' — '''''Tickborne Fever''''' — '''''Ruminant Anaplasmosis''''' — '''''TBF'''''
 
  
Caused By: '''''Anaplasma phagocytophilum''''', previously known as '''''Ehrlichia phagocytophila'''''
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*Caused by ''E. phagocytophila'' which has now been renamed as ''Anaplasma phagocytophilum''
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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
  
==Introduction==
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*Clinical signs
[[File:Anaplasmosis.jpg|thumb|200px|right|''Rickettsia'' spp. inside tick haemolymph cells. Sourced from Wikimedia Commons]]
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**Incubation period of 2 weeks; recovery in 2 weeks
[[File:Swollen tick-SteveFE.jpg|thumb|200px|right|''Ixodes'' tick. Sourced from Wikimedia commons]]
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**Fever, anorexia, reduced growth rates in young animals
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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**Reduced milk production, abortion, still birth
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**Leukopenia and thrombocytopenia
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**Causes immunosuppression in young lambs causing susceptibility to tick pyaemia and louping ill
  
Seasonal pasture fever occurs in cattle that are returned to tick infected pasture in the Spring.
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*Diagnosis
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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
  
Human granulocytic ehrlichiosis, the '''zoonotic''' form of TBF is a potentially '''fatal''' disease reported in the UK, Europe and USA.
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*Treatment and control
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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
  
==Signalment==
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==Literature Search==
TBF naturally affects primarily sheep and cattle, and less commonly, deer, horses and dogs.
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[[File:CABI logo.jpg|left|90px]]
  
==Distribution==
 
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]].'''
 
  
==Clinical Signs==
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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).
TBF causes '''multisystemic''' disease, causing cardiovascular, gastrointestinal, respiratory, reproductive and neurological signs, and also lymphadenopathy and wasting disease.
 
 
 
'''Severe haematological changes''' including profound [[:Category:Anaemia|'''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. <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>
 
 
 
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 |leucocytes]]''' in peripheral blood is confirmative.
 
 
 
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.
 
 
 
The parasites may be visible within the neutrophils in sections of liver and lung.
 
 
 
Antibodies can be detected using [[FAT|'''Indirect Immunofluorescence''' (IFAT)]], '''[[Complement Fixation]]''' and Immunoelectrophoresis (CIEP).
 
 
 
==Treatment==
 
''A. phagocytophilum'' is susceptible to '''oxytetracycline, sulphamethazine, sulphadimidine, doxycycline''' and '''trimethoprim-sulphonamides'''.
 
 
 
==Control==
 
[[Tick Control|Control of the tick vector ]]is expensive but effective.
 
Use of [[Ectoparasiticides |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.<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>
 
 
 
 
 
{{Learning
 
|flashcards = [[Tick-Borne Fever Flashcards]]
 
}}
 
 
 
 
 
==References==
 
<references/>
 
{{CABI source
 
|datasheet = [http://www.cabi.org/ahpc/?compid=3&dsid=61126&loadmodule=datasheet&page=2144&site=160 tick-borne fever]
 
|date = 6 June 2011
 
}}
 
 
<br><br><br>
 
<br><br><br>
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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''']
  
  
{{review}}
 
 
{{OpenPages}}
 
  
 
[[Category:Rickettsiales]][[Category:Cattle Bacteria]][[Category:Sheep Bacteria]][[Category:Goat Bacteria]]
 
[[Category:Rickettsiales]][[Category:Cattle Bacteria]][[Category:Sheep Bacteria]][[Category:Goat Bacteria]]
[[Category:Zoonoses]]
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[[Category:To_Do_-_Bacteria]][[Category:To Do - Medium]]
[[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]]
 
 
 
[[Category:Cardiovascular Diseases - Sheep]]
 
[[Category:Respiratory Diseases - Sheep]]
 
[[Category:Alimentary Diseases - Sheep]][[Category:Reproductive Diseases - Sheep]][[Category:Neurological Diseases - Sheep]]
 
[[Category:Lymphoreticular and Haematopoietic Diseases - Sheep]]
 
[[Category:CABI Expert Review]][[Category:CABI AHPC Pages]]
 
[[Category:Nick L]]
 
[[Category:Cardiology Section]]
 

Revision as of 16:02, 9 May 2011

Tick-borne fever

  • Caused by E. phagocytophila which has now been renamed as Anaplasma phagocytophilum
  • Affects ruminants in Europe
  • The tick Ixodes ricinis is the main vector
  • Animals remain carriers for up to 2 years, but are immune to reinfection
  • Clinical signs
    • Incubation period of 2 weeks; recovery in 2 weeks
    • Fever, anorexia, reduced growth rates in young animals
    • Reduced milk production, abortion, still birth
    • Leukopenia and thrombocytopenia
    • Causes immunosuppression in young lambs causing susceptibility to tick pyaemia and louping ill
  • Diagnosis
    • Intracytoplasmic morulae in neutrophils of Giemsa-stained blood smears during acute phase
    • Seroconversion detected by immunofluorescence
  • Treatment and control
    • Oxtetracycline
    • Tick control
    • Prophylactic tetracyclines for lambs during first few weeks of life

Literature Search

CABI logo.jpg


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).


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