 Reference Base  The treatment of eight square-lipped rhinoceros (Ceratoth... |
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| Location: |
World |
| Subject: |
Diseases - Parasites |
| Species: |
White Rhino |
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Bot fly larvae of the genus Gyrostigma commonly occur in white rhinoceros at Umfolosi, and as nematode egg counts on the faeces of the eight animals imported to Rhodesia showed a fairly high level of infestation, it appeared highly desirable to reduce their parasitic burdens to a minimum, in the hope that it might fall below the critical level necessary for their survival in their new environment.
As dipterous fly larvae and nematodes were the main parasites concerned (no evidence of trematodes or cestodes were found) the drug of choice to be used was an organophosphate Neguvon P, containing 75 per cent dimethyl-hydroxytrichlorethyl phosphonate.
The Neguvon P. was mixed with maize and meal gruel, and despite the fact that the rhinoceros were deprived of water for forty eight hours previously, they took several hours to consume the gruel, and in some cases not all of the gruel was consumed.
At the Kyle Dam Game Reserve, one rhinoceros, 'Nyoni', was test dosed at a rate of 44 mg/kg. Eighteen hours after dosing he was lying on his side, apparently off his food. No antidote was administered, and the next day he appeared to have recovered completely.
In view of the apparent toxicity, the remaining three were dosed at a level of 44 mg/Kg.
All four animals at the Matopos National Park received a dose of 44 mg/lb body weight.
Faecal worn egg counts were carried out once before and twice after treatment, the technique used being that described by Gordon and Whitlock. The results recorded are a mean of three counts made on each specimen. Attempts were made to recover all dead parasites passed in the faeces, but this was difficult due to the habit of the white rhinoceros to disturb its faeces immediately after defaecation. - epg = nematode eggs per gram
Weight Dose epg on day epg at 5 days epg at 14 days no. bots
kg gr before treat post-treatm post-treatment recovered
1 786 68 430 130 130 -
2 848 72 130 100 nil -
3 916 80 1500 100 32 -
4 841 72 65 nil nil -
5 1002 88 310 100 66 21
6 695 30.5 900 180 133 11
7 785 34.5 1430 300 266 10
8 1000 44 550 133 66 6
Mean 664 130 86
Only one animal out of five, dosed at a rate of 44 mg/lb exhibited transient toxic symptoms. None of the three dosed with the lower dose rate of mg/kg showed any signs of toxicity.
Both larvae were first noticed in the faeces 48 hours following dosing, and were still being passed 7 days later. The maximum recovered from one animal was 21. More might have been passed, and were either eaten by birds or disintegrated when the animal disturbed its faeces.
Pre-and post-dosing nematode egg counts are shown in Table 1. The counts of nos. 3 and 7 of 1,500 and 1,450 eggs per gram (e.p.g.) respectively are very high. The mean egg counts of the eight rhinoceros concerned were reduced from 664 to 86 e.p.g.
The method of administration appeared to be satisfactory. In most cases not all of the gruel was consumed, but as the dosage was high and effective results obtained, this did not matter.
From experience on Lake Kariba, black rhinoceros (Diceros bicornis) settle down to pen feeding after capture far more quickly than white rhinoceros. The black rhinoceros is very fond of ripe paw paws (Carica papaya) and will readily accept a half paw paw containing a dose of Neguvon P. The latter is now routine practice with all rhinoceros caught on the Lake Kariba during 'Operation Noah'.
The results of the pre-dosing faecal egg counts would appear to indicate that parasitism in white rhinoceros at Umfolosi exists at a relatively high level. This might be expected, due to the high concentration of the species in this area.
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