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Also Known As: '''''Pasture Fever''''' — '''''Tickborne Fever''''' — '''''Ruminant Anaplasmosis''''' — '''''TBF'''''
Caused By: '''''Anaplasma phagocytophilum''''', previously known as '''''Ehrlichia phagocytophila'''''
==Introduction==
[[File:Anaplasmosis.jpg|thumb|200px|right|''Rickettsia'' spp. inside tick haemolymph cells. Sourced from Wikimedia Commons]]
[[File:Swollen tick-SteveFE.jpg|thumb|200px|right|''Ixodes'' tick. Sourced from Wikimedia commons]]
Tick Borne Fever is a '''[[Rickettsiales |rickettsial]]''' disease affecting the '''[[Leucocytes |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 spp. |Ixodes]]''''' ticks. Both adults and nymphs can transmit the disease. Transmission is '''[[Tick Disease Transmission |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 [[: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
}}
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[[Category:Zoonoses]]
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