Observations on the aetoilogy of trachoma

Abstract

Researches into the aetiology of Trachoma have been shown to be important so as to:

(1). Encourage Prophylaxis.

(2). Facilitate early diagnosis and thus avoid invasion of this country by Trachomatous immigrants.

From the historical study of the disease it lias been seen that Trachoma, is an old established disease, of world wide distribution which may break out in epidemics particularly in armies and schools and which may be hampered in its spread by taking proper precautions.

In the section on the early views as to aetiology it has been shown that the contagiousness of the disease became universally recognised. After many more fantastic theories as to the cause had been propounded Trachoma, came to be regarded as due to a virus transmitted by the con¬ junctival secretion. Transmission was held to be most likely to occur when predisposing conditions were present preparing a nidus for or facilitating infection.

The most Important predisposing causes were shown to bet- Want of cleanliness, overcrowding, unfavourable occupational conditions, war service, school attendance, with its lack of care In avoiding contagion, and debilitating disease. Since the beginning of the search for the causal organism about thirty years ago many claims have been made that the organism was discovered. No proper confirmation however has been given to any work claiming a specific organism as the cause, nor were any very promising results obtained until the discovery of the Halberst'adter-tProwazek bodies. These are regarded as pathogenic organisms of diagnostic significance In Trachoma, but they are not yet proved to be the cause.

Researches with various organisms as possible causes for Trachoma having proved inconclusive, for the purpose of this Thesis observations were made as to the possibility of the cauaal organism being a spirochaete. The results obtained have been:-

(1). The camsal organism is not a spirochaete. Careful examination of specimens by two different methods 3% a. Dark Ground, b. Fontana films, failed to show apirochaetes.

(2). Examination of the Red Blood Count, Haemoglobin per¬ centage and Colour Index showed that Trachoma is associated with Anaemia and lowered vitality.

(3). Examination of the white cell count tended to show that Trachoma is an infection, a leucocytosis being obtained.

(4). A differential count of the Leucocytes in Blood Films showed an increase in the Lymphocytes indicating that the casual organism is most likely to be a protozonn. If the Halberstadter-Prowazek bodies be taken as the cause this may be an indication as to the true nature of the bodies.

(5). Though no spirochaetes were found the majority of the cases seemed to improve under treatment by instillation of a solution of Novarsenobillon into the conjunctival sac. The explanation of this may be that the arsenics preparation acts in this case not by toxic effect on any spirochaete but by a stimulating action on the tissues, or by a lethal action on any other parasite. The results obtained were sufficiently encouraging for one to suggest this as a method of treatment for Trachoma. The strength should be 0.3 grrn. to 3 cc. distilled water and the Interval between instillations not longer than three to four days. The cases/which .its use is contra indicated are those in an advanced cicatricial stage and those with severe irritable corneal conditions.

(6). The enquiry showed that the predisposing conditions previously enumerated are of importance in the dissemination of the disease.