MAST-CELLS AND EOSINOPHILS IN UPPER RESPI RATORY MUCOSA OF SHEEP INFECTED WITH ESTRUS-OVIS (LYNNE, 1761) LARVAE

Mast cells and eosinophils have been identified by differential staini ngs and counted in mucous membrane of nasal sepium, turbinates and sin us 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 t he cell numbers and their distribution among the septum, the turbinate s and the sinus and according to their position in mucous membrane, in terglandular chorion of sub-mucosa. In infected sheep, the mean number of most cells is twice the number present in parasite free animals. T he 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.