The Veterinary Record, Vol 138, Issue 18, 434-436
Copyright © 1996 by British Veterinary Association

Decoquinate and the control of experimental ovine toxoplasmosis

¹ Moredun Research Institute, 408 Gilmerton Road, Edinburgh EH17 7JH
² Moredun Animal Health, 408 Gilmerton Road, Edinburgh EH17 7JH
³ Rhône Mérieux, Spire Green Centre, Harlow, Essex CM19 5TS

Decoquinate was tested for its ability to reduce the effect of experimentally induced toxoplasmosis in pregnant ewes. Sheep were given decoquinate in their feed daily at either 2 mg or 1 mg/kg bodyweight from 10 days before an oral challenge with Toxoplasma gondii oocysts at 90 days of gestation, until lambing. Feeding decoquinate at the higher rate caused a delay in the onset of the febrile response to infection, reduced the overall severity of the fever and delayed the production of antibodies to the parasite. This treatment also reduced the placental damage caused by the parasite, lengthened the mean gestation period and increased the number and weight of live lambs, in comparison with ewes not fed decoquinate but challenged with T gondii oocysts. The treatment with 1 mg of decoquinate had smaller effects.