Difference between revisions of "Leptospirosis - Horses"
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'''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. | '''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. | ||
| − | '''Reproductive''': Leptospirosis can cause abortion, still birth or neonatal disease depending on the serovar and the stage of gestation when infected. | + | '''Reproductive''': Leptospirosis can cause 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 late term. |
'''Renal''': leptospirosis rarely causes urologic signs including polyuria/polydipsia, azotaemia, pyuria and haematuria. | '''Renal''': leptospirosis rarely causes urologic signs including polyuria/polydipsia, azotaemia, pyuria and haematuria. | ||
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A MAT or ELISA opn serum is a more sensitive diagnostic method. Paired titres 4 weeks apart are optimal. | A MAT or ELISA opn serum is a more sensitive diagnostic method. Paired titres 4 weeks apart are optimal. | ||
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| + | ===Ultrasound=== | ||
| + | Abdominal ultrasound is useful in assessing the degree of damage in the hepatic and renal forms of the disease. | ||
==Treatment== | ==Treatment== | ||
Revision as of 13:09, 21 August 2010
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This article is still under construction. |
Description
Leptospirosis is a disease caused by the bacteria 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.
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.
Diagnosis
Clinical signs
Infection with pathogenic Leptospira spp cause a bacteraemia with the following clinical signs
- Pyrexia
- Depression
- Lethargy
- Anorexia
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.
Reproductive: Leptospirosis can cause 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 late term.
Renal: leptospirosis rarely causes urologic signs including polyuria/polydipsia, azotaemia, pyuria and haematuria.
Hepatic: Horses with the hepatic form of the disease will bei icteric, pyrexic and lethargic.
Horses with subclinical infections or those in the carrier state are asymptomatic.
=Laboratory Tests
Culture of Leptospira is challenging but can be attempted from urine, blood and aqueous humour in antemortem diagnosis, or from liver, kidney, fetus or placenta in post mortem diagnosis.
A MAT or ELISA opn serum is a more sensitive diagnostic method. Paired titres 4 weeks apart are optimal.
Ultrasound
Abdominal ultrasound is useful in assessing the degree of damage in the hepatic and renal forms of the disease.
Treatment
Treatement should be directed towards the specific organ system affected.
Prognosis
References
- Merck & Co (2008) The Merck Veterinary Manual (Eighth Edition) Merial