Toxoplasmosis - Sheep
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This article is still under construction. |
Description
- 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