Effect of cysteine protease inhibitor (E64) on haematological changes of New Zealand rabbits experimentally infected with Trypanosoma brucei brucei

Abstract

This study was conducted to determine the in-vivo effect of cysteine protease inhibitor (CPI) E64 on the clinico-haematology of New Zealand rabbits experimentally infected with Trypanosoma brucei brucei. A total of forty (40) New Zealand rabbits of both sexes were divided into 8 groups (A – H) of 5 rabbits each. Group A was infected but untreated (infected control), group B was uninfected and untreated (normal control). Group C was infected/treated pre-infection with CPI (E64) at 0.5ml/kg once daily for 5 days, while group D was infected and treated from 14 days post infection with CPI at 0.5ml/kg once daily for 5 days. Group E was uninfected and treated with CPI at 0.5ml/kg once daily for 5 days, while group F was infected and treated with a single standard dose of 3.5mg/kg of diminazene aceturate (Veriben® ) by day 14. Group G was uninfected and treated with a single standard dose of Veriben® at 3.5mg/kg, while group H was infected and treated with of Veriben® at 3.5mg/kg and CPI at 0.5ml/kg once daily for 5 days at the peak of parasitaemia by day 14 postinfection (P.I). The animals were monitored for parasitaemia, haematological parameters such as red blood cell count, packed cell volume and haemoglobin concentration. The result showed that the animals became parasitaemic 7 days P.I with mean values of 7.75 ± 0.95, 8.50 ± 0.57, 8.00 ± 0.15, 8.00 ± 0.15 and 8.50 ± 0.57, in Groups A, C, D, F and H, respectively. Clinical signs such as anorexia, pyrexia, alopecia, and emaciation were seen. Haematological changes noticed as parasitaemia progressed include anaemia characterized by a significant decline in mean packed cell volume, haemoglobin concentration and red blood cell count was noticed in infected groups. Cysteine protease inhibitor (E64) alone was ineffective in ameliorating the deleterious effect of Trypanosoma brucei brucei especially against parasitaemia and haematological parameters.

Keywords: Anaemia, Cysteine protease inhibitor, Haematology , Parasitaemia, Trypanosoma brucei brucei