Toxoplasmosis in sheep. II. The ability of a live vaccine to prevent lamb losses after an intravenous challenge with Toxoplasma gondii

Authors: Te Punga WA, O'Connell E, Wilkins MF
Publication: New Zealand Veterinary Journal, Volume 36, Issue 1, pp 1-4, Mar 1988
Publisher: Taylor and Francis

Animal type: Livestock, Production animal, Ruminant, Sheep
Subject Terms: Abortion/stillbirth, Animal remedies/veterinary medicines, Reproduction, Immune system/immunology, Protozoa, Reproduction - female, Disease/defect, Zoonosis, Infectious disease, Vaccination, Public health
Article class: Scientific Article

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Abstract: Two-tooth ewes (n=48) were immunized pre-tupping with a live Toxoplasma gondii vaccine. At midpregnancy these ewes were challenged intravenously with 1 x 10⁵ live T. gondii tachyzoites. The strain of T. gondii used for vaccination was an “incomplete” strain that did not produce oocysts. It was derived by continuous twice weekly passage in mice. The lambing percentage for ewes immunized with the live vaccine was significantly higher (P<0.001 normal score) than non-vaccinated control ewes. However, vaccination did not prevent foetal or placental infection. The serological response to vaccination and challenge was measured by both the Dye test and the Indirect Haemagglutination test. No significant relationship between titre of antibody and protection in the vaccinated ewes was observed.

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