Mast cells and eosinophils in upper respiratory mucosa of sheep infected with Oestrus ovis (Lynne, 1761) larvae

Mast cells and eosinophils have been identified by differential stainings and counted in mucous membrane of nasal sepium, turbinates and sinus of 77 ewes naturally infected with Oestrus ovis. Results have been compared with those of nine parasite free lambs. Anova tests indicate significant differences between infected and parasite-free sheep for the cell numbers and their distribution among the septum, the turbinates and the sinus and according to their position in mucous membrane, interglandular chorion of sub-mucosa. In infected sheep, the mean number of most cells is twice the number present in parasite free animals. The burdens of eosinophils are multiplied by 17 for the sepium, 29 far the turbinates and 58 for the sinus. The hypothesis of the development of an hypersensitivity phenomenon in ovine oestrosis is sustained by these results.