Staining of the inclusion bodies of trachoma and inclusion conjunctivitis.

THE first description of the inclusion bodies of trachoma was made by Halberstaedter and von Prowazek following the examination of Giemsa-stained scrapings from the conjunctivae of baboons which had been inoculated with secretions from trachomatous patients (cf. Julianelle, 1938). Since then Giemsa and its modifications have held prime place as a means of demonstrating these structures and this position has been upheld by the recommendation of its use in the Second Report of the WHO Expert Committee on Trachoma (1955): "for trachoma studies-for the examination of smears and scrapings from the conjunctiva". Although Giemsa may well constitute a standard reference of staining, certain problems arise from its use: first, the prolonged staining time and the need for solutions of controlled pH; secondly, the superficial similarity between the Giemsa-stained HP inclusion and a number of other intracellular appearances (e.g. granular cytoplasm, nuclear prolapse), which, even in experienced hands, militates against the speedy examination of smears; thirdly, the difficulty of detecting HP inclusions in thick clumps of tissue; finally, the difficulty in distinguishing the full details of inclusion morphology when this overlies a deeply-stained cell nucleus. These factors have led to a search for suitable alternative stains. Among these are Wright's modification of Giemsa, Castaneda's stain, Lindner's contrast stain, Macchiavello's stain, and Poleff's stain. Of these most have proved of no greater value than Giemsa, while others, such as Poleff's methylene blue, have been found unreliable (Thygeson, 1955), owing to the ease with which various intracytoplasmic structures may simulate HP inclusions. Despite the recommendation in the First Report of the WHO Expert Committee on Trachoma (1952) ". . . the development of rapid methods for the detention of inclusion bodies: Thick scrapings. Iodine stain.. little further work appears to have been done, except that of Dark (1955), confirming the earlier studies of Rice (1936) and Thygeson (1938), on the staining by iodine of the glycogen-containing matrix of the HP inclusion. During the course of a recent project on the aetiology of trachoma this problem of speedy and accurate detection assumed prominence as it was