Abstract

Alloxan monohydrate was used to induce diabetes in rats, and then followed post infection with Trypanosoma congolense and Trypanosoma brucei to determine the impact of diabetes on the course of trypanosome infection. Significant (P<0.05) hyperglycaemia occurred in the alloxan treated rats starting on day seven to the end of the experiment. Trypanosome infection did not affect the glycaemic status of either the normal or the hyperglycaemic rats. The mean prepatent period (MPP) was significantly (P<0.05) longer in the diabetic T. brucei-infected rats (5.6±0.23 days) than the non-diabetics (3.8±0.34 days) whereas in the T. congolense it was similar in both the diabetic (13.1±0.73days) and the non-diabetic (13.3±0.67 days). The levels of parasitaemia which were comparable in the diabetic and non-diabetic groups increased progressively until death of the rats. The mean survival time (MST) for the diabetic T. brucei-infected rats (17.2±0.86 days) was not significantly (P=0.49) different from that of the non-diabetics (19.5±1.15 days) while that of the diabetic T. congolense (34.8±4.15 days) was significantly (P<0.001) longer than that of the non-diabetics (25.7±2.1 days). T. brucei infection in the diabetics was significantly (P<0.001) more acute than T. congolense (MST, 17.2±0.86 versus 34.8±4.15 days) unlike in the non-diabetic (MST, 19.5±1.15 versus 25.67±2.11 days, P=0.08). The red blood cell parameters (PCV, HB and RBC) were significantly (P<0.05) decreased by trypanosome infections, unaffected by the diabetic status but was trypanosome species dependent, being significantly lower in the T. brucei than T. congolense-infected rats. A significant (P<0.05) decrease in the percentage body weight gains between the diabetic and the non-diabetic controls occurred as a result of the weight decreasing effect of diabetes mellitus. It was thus concluded that the course of T. brucei and T. congolense infections was not significantly altered in alloxan-induced diabetic rats, and trypanosome infection may not confound the results of blood glucose monitoring for the diagnosis of diabetes.

Key words: Trypanosoma brucei, Trypanosoma congolense, rat, diabetes mellitus.