Dust and the incidence of severe trachoma.

A dry dusty climate has long been noted as a factor associated with a high incidence of trachoma and the complications of that disease (Duke-Elder, 1938). Epidemiological studies, recently carried out in India by means of an exhaustive random sample survey by the Trachoma Pilot Project-India, show conclusively that the incidence of trachoma is highest in the dust-laden north and north-westerly areas of the sub-continent, while it is lowest in the south and east (Gupta and Preobragenski, 1964). An earlier survey based on figures obtained from eye hospitals and clinics all over India demonstrated an almost exactly similar distribution (Ursekar, 1955). The work of Gupta and Preobragenski also showed that new cases of trachoma in India reach their peak incidence during the dry pre-monsoon and post-monsoon periods (Cooper, 1964). The present writer, working with figures from ophthalmic clinics in Ghana, noted a higher incidence of trachoma in the dry areas of the Northern Territories than in the coastal belt (Sarkies, 1952).