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==Description==
==Description==
'''Leptospirosis''' is a disease caused by the bacteria [[Leptospira|''Leptospira interrogans'']]. It affects domestic species, wildlife and has zoonotic potential. There are several different serovars which vary in pathogenesis and their host specificity. Most infections result in a self limiting pyrexia and anorexia, however occasionally the condition is more serious causing recurrent uveitis, abortion, or renal and hepatic disease. Recurrent uveitis is the most important clinical syndrome associated with Leptospirosis. The association has been well recognised for many years, originally thought to be an immune-mediated disease involving a cross rection between antibodies against leptospira and ocular tissues. There is now additional evidence that live leptospira persist in the ocular fluids, providing continuous antigentic stimulation resulting in high antibodies titres in aqueous humour in comparision to the the serum, suggesting that the eye is an immune privilegded site.
'''Leptospirosis''' is a disease caused by the bacteria [[Leptospira|''Leptospira interrogans'']]. It affects domestic species, wildlife and has zoonotic potential. There are several different serovars which vary in pathogenesis and their host specificity. Most infections result in a self limiting pyrexia and anorexia, however occasionally the condition is more serious causing recurrent uveitis, abortion, or renal and hepatic disease. Recurrent uveitis is the most important clinical syndrome associated with Leptospirosis. The association has been well recognised for many years, originally thought to be an immune-mediated disease involving a cross reaction between antibodies against leptospira and ocular tissues. There is now additional evidence that live leptospira persist in the ocular fluids, providing continuous antigetic stimulation resulting in high antibodies titres in aqueous humour in comparison to the serum, suggesting that the eye is an immune privileged site.
==Signalment==
==Signalment==
Exposure to the disease is worldwide, with the predominent serovar varying with location. Serological studies show that exposure is high but clinical disease is low.
Exposure to the disease is worldwide, with the predominant serovar varying with location. Serological studies show that exposure is high but clinical disease is low.
==Diagnosis==
==Diagnosis==
===Clinical signs===
===Clinical signs===
Infection with pathogenic Leptospira spp cause a bacteraemia with the following clinical signs
Infection with pathogenic Leptospira species cause a bacteraemia with the following clinical signs
* Pyrexia
* Pyrexia
* Depression
* Depression
The disease can then invade a specific organ system resulting in associated clinical signs:
The disease can then invade a specific organ system resulting in associated clinical signs:
'''Opthalmic''': The initial signs are blephrospasm, increased lacrimation, photophobia and corneal oedema, with progression to retinal detachment, synechia formation, and cataracts. Chronic leptospirosis causes recurrent uvietis, typically signs develop 2-8 months after initial infection. Up to 67% of recurrent uveitis cases are due to leptospirosis.
'''Ophthalmic''': The initial signs are blephrospasm, increased lacrimation, photophobia and corneal oedema, with progression to retinal detachment, synechia formation, and cataracts. Chronic leptospirosis causes recurrent uveitis, typically signs develop 2-8 months after initial infection. Up to 67% of recurrent uveitis cases are due to leptospirosis.
'''Reproductive''': Leptospirosis can cause placentitis, abortion, still birth or neonatal disease depending on the serovar and the stage of gestation when infected. Approximately 3-4% of equine abortions are caused by Leptospirosis, and are most frequently due to serovar Pomona, or occasionally Harjo. Abortion is usually late term, at 9 months of gestation.
'''Reproductive''': Leptospirosis can cause placentitis, abortion, still birth or neonatal disease depending on the serovar and the stage of gestation when infected. Approximately 3-4% of equine abortions are caused by Leptospirosis, and are most frequently due to serovar Pomona, or occasionally Harjo. Abortion is usually late term, at 9 months of gestation.
'''Renal''': leptospirosis rarely causes acute renal failure, signs include polyuria/polydipsia, azotaemia, pyuria and haematuria.
'''Renal''': leptospirosis rarely causes acute renal failure; signs include polyuria/polydipsia, azotaemia, pyuria and haematuria.
'''Hepatic''': Horses with the hepatic form of the disease will bei icteric, pyrexic and lethargic.
'''Hepatic''': Horses with the hepatic form of the disease will be icteric, pyrexic and lethargic.
Horses with subclinical infections or those in the carrier state are asymptomatic.
Horses with subclinical infections or those in the carrier state are asymptomatic.
==Treatment==
==Treatment==
Treatment should be directed towards the specific organ system affected.
Systemic antibiotics are indicated for pyrexic horses and those with acute renal failure. Appropriate anitbiotics include pencillins, cephalosporins, enrofloxacin and tetracycline. IV fluid therapy is also warranted as supportive therapy in cases of acute renal failure.
Systemic antibiotics are indicated for pyrexic horses and those with acute renal failure. Appropriate antibiotics include pencillins, cephalosporins, enrofloxacin and tetracycline. IV fluid therapy is also warranted as supportive therapy in cases of acute renal failure.
==Prognosis==
==Prognosis==
Prognosis depends on the severity of the disease and the degree of organ involvement. In opthalmic cases recovery may be incomplete, alternating between times of acute disease and symptom-free periods. In cases of abortion the mare will usually recover without complications. Prognosis is guarded for the renal, hepatic and neonatal syndromes in acute and severe cases.
Prognosis depends on the severity of the disease and the degree of organ involvement. In ophthalmic cases recovery may be incomplete, alternating between times of acute disease and symptom-free periods. In cases of abortion the mare will usually recover without complications. Prognosis is guarded for the renal, hepatic and neonatal syndromes in acute and severe cases.
==References==
==References==