 Reference Base  Lesions in the vicinity of the eye of the white rhinocero... |
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Young, E., 1965. Lesions in the vicinity of the eye of the white rhinoceros, Diceros simus. International Zoo Yearbook 5: 194-195
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| Location: |
Africa - Southern Africa - South Africa |
| Subject: |
Diseases |
| Species: |
White Rhino |
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Over the past few years, a number of White rhinoceroses were encountered with lesions in the vicinity of the eyes:
1. A post-mortem examination carried out on the carcass of an adult female, which had been brought to Pretoria Zoo to be prepared for mounting at the Transvaal Museum, revealed the presence of numerous exostoses round the orbits of the eye. One of these outgrowths was approximately z cm. long and it almost occluded the proximal opening of the naso-lacrimal canal.
2. During November 1963, our young White rhino bull, 'Ntjebe', developed ulcerations at the medial canthus of both eyes. These ulceration were 1 cm. deep and 3 cm. long. This case is described below in more detail.
3. During March 1964, similar lesions, as in Case No. 2 were observed in a White rhino in the Umfolozi Nature Reserve.
4. A White rhino in the Umfolozi Nature Reserve became completely blind as the result of extensive cauliflower-like growths which covered the entire surface of both eyes.
5. During November 1953 a young female, transferred from Natal to Pretoria Zoo, developed lesions similar to those described above in Case No. z. Surgical and medicinal treatment, as well as radio-active therapy over a period of ten years all proved unsuccessful. Granulomatous growths, which developed from these lesions, eventually assumed such widespread proportion as to indude the third eyelid and part of the surface of both eyes. For humane reasons, the animal had to be destroyed.
A close correlation seems to exist between the five cases described above. It is suspected that
injuries are the primary cause of such lesions.
It is quite possible that the various lesions represent different developmental phases of the same condition.
In Case No. 2, where ulceration were present in the medial canthus of bodi eyes, it was noticed that tears were running over the cheeks while the nostrils remained relatively dry. This led to the conclusion that the nasolacrimal canals were blocked; a suspicion that was confirmed when 2 per cent Sodium fluorescein was dripped into the eyes. The fluid drained over the cheeks and did not appear in the nostrils as was the case when the experiment was repeated with a healthy animal. Case No. a is continually involved in fights with his female companion and the blocking of the ducts could have been caused by bruising, chronic inflammation or exostoses in the vicinity of the naso-lacrimal duct.
The abnormal drainage of tears caused a softening of the skin in the vicinity of the eyes, and large numbers of domestic flies, Musca domestica, were attracted to the area. The rhino alleviated the irritation by rubbing its head against hard objects. The lesions caused in that way soon became infected and purulent. At a later stage, the ulcers were lined with granulation tissue. The lesions probably would have developed into granulomata if the animal had received no treatment.
Apart from a variety of bacteria, even Habronema larvae could have been deposited 'by house flies. Such larvae could have been responsible for the formation of granulomata as in the case of 'cutaneous habronemiasis' in horses, or 'cutaneous filariasis', as described in the Black rhino, Diceros bicornis.
Treatment.
The lesions of Case No. a were treated three. times a day, according to the following formulation:
Cocaine 1 per cent (local anaesthetic)
Chloromycetin 5 per cent (broad spectrum antibiotic)
Prednicilone 1 per cent (corticoid)
Methyl cellulose qs.ad. (base, forming layer over the lesion)
The ulcers healed within two weeks and only narrow scars remained to indicate the site of the original lesions. Similar lesions, however,again developed after four weeks. The above mixture was then applied three times a day, with Chloromycetin replaced by 5 per cent Polymixin and 5 per cent Neomycin. After a period of three weeks, the lesions again healed completely. However, it was experimentally determined with Sodium fluorescein that the naso-lacrimal ducts were still obstructed. Unless these ducts are opened surgically, a recurrence of the lesions in the same region can be expected.
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