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Ovine Brucellosis (view source)

Revision as of 10:38, 6 June 2011

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[[File:B ovis.jpg|thumb|200px|right|Bisected testicle form ''B. ovis'' ram showing grossly enlarged epididymis with fibrous tissue bands. AFSPH Iowa State]]

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~~== Introduction ==~~

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~~This is a disease in sheep caused by either~~ ''~~[[Brucella melitensis]]~~'' or ''~~[[Brucella ovis]]~~''. ''~~B. mellitensis~~'' ~~also causes disease in goats, but~~ ''B. ovis'' ~~affects only sheep. It is a disease that causes abortion, stillbirths and the birth of weak lambs and is prevalent in Eurpoe, America and Australia~~.

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Also Known As – '''''Ram epididymitis''''' – '''''Orchitis''''' – '''''Ovine Contagious Epididymitis''''' – '''''Brucella ovis Epididymitis'''''.

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Caused By – ''[[Brucella ovis]]''

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==Introduction==

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Ovine brucellosis causes '''reproductive''' disease in sheep, mainly in '''rams'''.

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~~== Clinical Signs ==~~

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B. ovis is the least virulent of all the [[Brucella species]].

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''~~B. mellitensis~~'' ~~is more severe in goats than sheep~~. ~~Late abortion, still births or births of weak lambs are seen~~. ~~With ''B. ovis'', clinical signs~~ in ~~ewes are rarely seen and abortions, stillbirths and weak lambs are rare. Signs~~ are ~~seen mainly in rams and include [[Ovine Epididymitis|epididymitis]] and orchitis~~.

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The disease is on Lost B of the ''Office des International des Epizooties'' [www.oie.int/ (OIE)]

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==Signalment==

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Unique to sheep

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==Distribution==

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Present in all countries where sheep are intensively farmed.

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Transmitted mainly through '''semen''' but shedding is unreliable.

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~~== Diagnosis ==~~

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Ewes can also act as indirect vectors for brucellosis if they mate with both an infected and uninfected ram during the same oestrus cycle.

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~~Diagnosis is by complement fixation, culture of organism or demonstration of the organism in tissue.~~

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Abortion materials and vaginal discharge also contain [[Brucella species | brucella]] organisms

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Brucellosis is not considered zoonotic.

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==Clinical Signs==

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'''Epididymitis''' in rams – '''swelling''' and enlargement of [[Testes and Epididymis - Anatomy & Physiology | '''testes''']], scrotum, [[Penis - Anatomy & Physiology | '''penis''']] and prepuce.

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~~== Control ==~~

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Decreased reproductive performance due to '''impaired [[Spermatogenesis and Spermiation - Anatomy & Physiology | spermatogenesis]]'''.

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~~Test and slaughter is applied where the disease is exotic~~.

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Testicular '''atrophy''' occurs in chronic infections.

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Occasionally also '''abortion''' in ewes and weak lambs. This only occurs in ewes exposed in the first two trimesters or pregnancy, due to placental necrosis.

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==Diagnosis==

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Palpation of the testes is suggestive but not definitive.

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Specific '''immunofluorescent''' staining of semen smears is confirmatory.

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''Brucella'' organisms can also be '''isolated''' from the epididymis and accessory sex glands at necropsy, although excretion is intermittent so false negatives are not uncommon.

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[[ELISA Testing | '''ELISA''']] and '''Complement Fixation''' are also commonly used for serological diagnosis.

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==Treatment==

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'''Antibiotic''' therapy is very expensive, prolonged and ineffective.

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==Control==

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'''Testing and culling''' of breeding stock is essential to ensure carriers are not present within a flock.

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No vaccine is available for B. ovis and vaccination against B melitensis can interfere with serological diagnosis.

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==References==

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Animal Health & Production Compendium, Brucellosis (B ovis) datasheet, accessed 06/06/2011 @ http://www.cabi.org/ahpc/

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[[Category:To Do - CABI review]]

[[Category:Reproductive Diseases - Sheep]][[Category:Reproductive System - Pathology]]

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~~[[Category:To Do - Steph]]~~

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