Comparative biochemical and pathological changes in some laboratory animals experimentally infected with Trypanosoma brucei and their responses to diminazene diaceturate (Veriben®) therapy

ObjectiveTo compare the biochemical and pathological changes of Trypanosoma brucei brucei infected mice, rats and rabbits, and study the chemotherapeutic effects according to standard criteria.MethodsA total of 20 Balb/c Albino mice, 20 Wister Albino rats and 20 New Zealand rabbits, all adults and of both sexes were used in the study. Each rodent group was divided into four groups (A, B, C and D) of five animals each. Animals in Groups A and C were individually infected with 0.5 mL of blood from donor rats containing 1.5 × 106Trypanasoma brucei brucei, while Groups B and D remained uninfected. The animals were later treated like this: Group A (infected and untreated control), Group B (uninfected and untreated control), Group C (infected and treated) and Group D (uninfected and treated). The treatment was administered on Day 12 after infection.ResultsThe prepatent period for mice and rats was 4 days while that for rabbits was 8 days. There was a significant (P < 0.05) increase in levels of liver enzymes and serum metabolites which were more marked among the mice and rats than rabbits. These changes were modulated to their preinfection values in the infected treated animals. At necropsy, all animals showed splenomegaly, hepatomegaly and nephritis. However, cardiomegaly was exclusive to the rabbits. Histopathologically, degenerative changes were observed in both the liver and kidneys which were more severe among mice and rats and moderate in rabbits. Spleen of mice showed giant macrophages, while that of the rats showed epithelioid giant cells. However, spleen of rabbits showed haemosiderosis and eosinophilic infiltrations. Hydrophobic degeneration, necrosis and mononuclear cell infiltrations in the myocardium were observed only among rabbits.ConclusionsDiminazene diaceturate was able to ameliorate the various biochemical and pathological changes which were suggestive of severe liver and kidney dysfunctions with greater intensity occurring among mice and rats as compared to rabbits. Therefore, it suggested that mice and rats could be better animal models for studying the disease than rabbits.