Difference between revisions of "Toxoplasmosis - Sheep"
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==Description== | ==Description== | ||
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| + | Toxoplasmosis is caused by a parasitic organism called Toxoplasma gondii, a protozoan. It can infect most animals and birds, including people, and is found throughout the world. Members of the cat family are important in the spread of toxoplasmosis, as they shed the oocysts (eggs) of the organism in their faeces for a period following infection. The organism is an important cause of abortion and the birth of stillborn lambs in sheep and occasionally in goats. Infection with toxoplasma may cause problems for pregnant women and for people whose immune system is adversely affected for another reason. | ||
*Sheep | *Sheep | ||
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**Infection during the second trimester leads to foetal death and mummification | **Infection during the second trimester leads to foetal death and mummification | ||
**Infection during the last trimester leads to a weak or stillborn lamb | **Infection during the last trimester leads to a weak or stillborn lamb | ||
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==Signalment== | ==Signalment== | ||
Revision as of 13:54, 13 August 2010
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This article is still under construction. |
Description
Toxoplasmosis is caused by a parasitic organism called Toxoplasma gondii, a protozoan. It can infect most animals and birds, including people, and is found throughout the world. Members of the cat family are important in the spread of toxoplasmosis, as they shed the oocysts (eggs) of the organism in their faeces for a period following infection. The organism is an important cause of abortion and the birth of stillborn lambs in sheep and occasionally in goats. Infection with toxoplasma may cause problems for pregnant women and for people whose immune system is adversely affected for another reason.
- Sheep
- Mostly asymptomatic
- However, if a non-immune ewe is infected during pregnancy the consequences will be serious
- Infection during the first trimester leads to resorption
- Infection during the second trimester leads to foetal death and mummification
- Infection during the last trimester leads to a weak or stillborn lamb
Signalment
Diagnosis
Clinical Signs
- Clinical outbreaks of toxoplasmosis are sporadic
- Immunity is acquired before tupping
- Significant ill-effects are unlikely if immune ewes are infected during pregnancy
- Not shed from sheep to sheep so predicting outbreaks is difficult
Laboratory Tests
Pathology
Aborted ewes show focal necrotic placentitis with white lesions in the cotyledons and foetal tissue
Treatment
- Toxovax vaccine
- Live, avirulent strain of Toxoplasma
- Does not form bradyzoites or tissue cysts
- Killed by host immune system
- Single dose given 6 weeks before tupping
- Protects for 2 years
- Immunity boosted by natural challenge
- Medicated feed can be given daily during the main risk period
- 14 weeks before lambing
- The best method of protection is to prevent cats from contaminating the pasture, lambing sheds and feed stores