Transmission of a chlamydia-like agent isolated from contagious conjunctivo-keratitis of sheep

Abstract

Extract

A specific ophthalmia of sheep known contagious conjunctival — keratitis(CCK), and in Australasia more commonly as “pink-eye”, has been recolgnized for many years in the major sheep farming areas of the world. Older names such as snow blindness or heather blindness suggest that originally shepherds associated changes of climate and husbandry with outbreaks of the condition. and presumably its contagiousness was not suspected. The first significant report incriminating a micro-olrganism in the aetiology of the disease arose from work carried out in South Africa where Coles (1931) Bad observed Rickettsia-like structures in the conjunctival cells of sheep affected with CCK. Presence of the cytoplasmic inclusions was confirmed by Donatien and Lestoquard (1938) who suggested that the pleomorphic forms seen were stages in a lifecycle of the causative agent. Both in the changes within epithelial cells and also in clinical features of the conjunctivo-keratitis, the same authors noted similarities between CCK and the serious blinding disease of man, trachoma. Further evidence confirming the likeness was provided by Dickinson and Cooper (1959) who recognized large intra-cytoplasmic micro-colonies or plaques of the suspected CCK agent which were similar in appearance to the glycogen matrix inclusions seen in epithelial cells of trachomatous patients.