The effect of two challenge doses of Dictyocaulus filaria on the acquired immunity of sheep vaccinated with "Filiraq".

Abstract

Twenty six lambs divided into four groups were used to study the effect of experimental infection with two challenge doses of D.filaria ( 100 & 300 larvae / Kg. B. W.) on the aquired immunity after vaccination with irradiated larval vaccine “ Filiraq”. The clinical symptoms , eosinophi lic response, blood picture, faecal larval counts, gross pathological changes & adult worm counts in the lungs were studied ... The results showed that a high dose of challenge (300 LI kg) prevents the development of expected acquired immunity, however the other vaccinated & challenged group ( 100 LI Kg B.W ) showed good level of acquired immunity in comparison with other group.

Keywords

• sheep
• Dictyocaulus filaria
• immunity
• Filiraq