N. Maina, J.M. Ngotho, Z.K. Njiru, W.M. Karanja, C.O. Gem, S.M. Karanja, J.K. Kibugu and J.M. Ndung’u
Kenya Trypanosomiasis Research Institute (KETRI), P.O.Box 362, Kikuyu, Kenya
ABSTRACT
The efficacy of a diminazene aceturate formulation, Trypan® (Ataros GmbH and Co.) which was recently developed and recommended for camel trypanosomosis, was tested in 11 (1 to 3 year old) dromedary camels. The animals were divided into 3 groups; 1, 2 and 3, comprising 4, 3 and 4 camels, respectively. Groups 2 and 3 camels were inoculated with Trypanosoma evansi KETRI 2455 (1 x 104 trypanosomes) via intravenous injection while group 1 was left uninfected. Clinical examination and parasitaemia determination were done daily whereas blood for haematology was collected weekly. Camels in group 2 and 3 were treated with Trypan at 3.5 mg/kg bwt intramuscularly (IM) at the onset of parasitaemia (day 8 post infection) and at peak parasitaemia (day 10 post infection), respectively. The control animals (group 1) were treated with Trypan® at 3.5 mg/kg bwt IM and observed daily for overt signs of toxicity. The camels did not show any sign of toxicity during the 3 months experimental period. Treatment with Trypan® at the onset of parasitaemia (group 2) resulted in clearance of trypanosomes within 18 hours. The animals however relapsed ten days after treatment and were treated curatively with 0.25 mg/kg bwt melarsomine. Camels treated at peak parasitaemia with Trypan® also became aparasitaemic within 18 hours. The clinical condition of the camels severely deteriorated despite no relapse. The camel were euthaniased 5 days post treatment to alleviate further suffering. At post-mortem there was exudative pneumonia, haemorrhagic gastroenteritis and myocarditis. Histopathology revealed involvement of the central nervous system, with heavy cellular infiltration and congestion of blood vessels. This implies that Trypan® suspension may not be effective in curing camels with acute T. evansi infections.
Key words : Dromedary camels, Trypan® (diminazene aceturate), Trypanosoma evansi
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