|Year : 1981 | Volume
| Issue : 3 | Page : 257-260
Persistence of chlamydial antigen in conjunctiva and lacrimal sac of monkeys
VM Mahajan, Ranjana Niroola, Lalit P Agarwal
Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
V M Mahajan
Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, Ansari Nagar, New Delhi
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Mahajan V M, Niroola R, Agarwal LP. Persistence of chlamydial antigen in conjunctiva and lacrimal sac of monkeys. Indian J Ophthalmol 1981;29:257-60
The problem of recurrences in trachoma in endemic countries is still menacing. The question of whether reinfection occurs with a fresh agent or by recrudescence of an old dying infection still remains unscrutinised. This study was undertaken to find out the time period for which chlamydia can persist in the ocular tissues (especially the conjunctiva and the lacrimal sacs) of monkeys after an experimental infection.
| Materials and methods|| |
Sixteen Indian rhesus monkeys free from spontaneous folliculosis and follicular conjunctivitis were used for the study.
The inoculation was carried out by rubbing a cotton swab soaked in infected yolk sac suspension of Bour strain containing 10 3.6 ELD 50 /0.2 ml. Five eyes kept as control were similarly inoculated with normal yolk sac suspension.
The clinical findings were scored by the system of W.H.O.
The conjunctival scrapings collected regularly were studied after Giemsa and fluorescent antibody (FA) staining. Reisolation attempts were made using ambryonated eggs and confirmation was done by staining the yolk sac membranes with Gimenez stain.
The lacrimal sac was also investigated similarly for reisolation, fluorescent staining of impression smears and histopathological examination by H & E as well as by Giemsa staining.
| Observations|| |
Conjunctival congestion persisted in 57% of the eyes upto 90 days when the experiment was terminated. Follicles [Figure - 1] which appeared after 20 days were there in 71% eyes, while the papillary hyperplasia persisted in 43% of the test eyes till the end. Almost always, one third of tarsus was involved. With Giemsa staining intracytoplasmic inclusions were seen in 25/57 slides (44%) examined over a period of 90 days. Five out of seven scrapings on the 90th day showed the presence of inclusions. Other cytological features were the presence of polymorphonuclear cells, extra cellular elementary bodies, cytoplasmic vacuolation, nuclear extrusions and germinal centre cells [Figure - 2]. Out of 57 smears studied by FA technique, 40 (70%) showed intracytoplasmic inclusions. On the 90th day, 86% of the scrapings were positive [Figure - 3]. Successful reisolations could be made upto the 90th day.
The H & E stained sections showed changes in the epithelium of 70% of the lacrimal sacs. Changes were mainly the squamous cell metaplasia, exfoliation of superficial epithelium or its hyperplasia [Figure - 4]. Giemsa stained sections of the sac removed on the 90th day showed numerous intracycloplasmic inclusions [Figure - 5]. However, the isolation attempts and the demonstration of inclusions by FA technique in the impression smears of the lacrimal sac were unsuccessful.
| Discussion|| |
After a single inoculation of Bour strain of Chlamydia trachomatis all the monkeys developed a clinical picture akin to that described by several others,,. The persistence of chlamydia in the infected conjunctiva and lacrimal sac studied by the various laboratory procedures clearly showed that the chlamydial activity was perceptible till the 90th post-inoculation day. Our findings were further substantiated by the demonstration of inclusions in the conjunctival cells till the 90th day by Giemsa and FA procedures and the successful reisolation even on the 90th day specimen which showed that the organism was still viable. Had a more sensitive method like the irradiated or IUDR treated tissue culture been used, the efficiency of reisolation could have been definitely more. Gale et al have reported reisolation ten years after the infection in Taiwan monkeys.
The histopathological changes in the lacrimal sac tissue were suggestive of chronic irritation. These changes were progressive in nature and visible even on the 90th day which were in conformation with others,. Though no reisolation could be possible, the numerous intracytoplasmic inclusions in Giemsa stained section of the lacrimal sac (90th day) alone implies an active pathology and deserves a special mention. if it is true, it would mean that the duration of antitrachoma treatment should be redetermined, the possibility of irrigating the sac with antitrachoma agent should be considered, the role of chlamydia in dacryocystitis and post-operative iridocylitis and keratitis especially in trachoma endemic countries should be evaluated.
| Summary|| |
Single inoculation of Bour strain of Chlamydia trachomatis in the conjuctival sac of Indian Rhesus monkeys led to the development of chlamydial infection which remained active in a large number of animals upto 90 days. Inclusion positivity in conjunctival scrapings by Giemsa stain was 43.85% as compared to 70.17% by fluorescent antibody technique (FAT) thus confirming the superiority of the latter over the former. FAT was able to detect chlamydia even when the clinical signs were not manifest. Over-all reisolation rate in embryonating eggs was 25% only. The agent was however, detectable by one or the other means upto the 90th day in conjunctiva as well as lacrimal sac tissue. Histopathological changes in the latter were suggestive of chronic infection and indicative of its being a possible reservoir for chlamydia.
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[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5]