Comparative pathogenicity of Trypanosoma brucei rhodesiense strains in Swiss white mice and Mastomys natalensis rats.

Abstract We evaluated Mastomys natelensis rat as an animal model for Rhodesian sleeping sickness. Parasitaemia, clinical and pathological characteristics induced by T. b. rhodesiense isolates, KETRI 3439, 3622 and 3637 were compared in Mastomys rats and Swiss white mice. Each isolate was intra-peritonially injected in mice and rat groups ( n  = 12) at 1 × 10 4 trypanosomes/0.2 mL. Pre-patent period (PP) range for KETRI 3439 and KETRI 3622-groups was 3–6 days for mice and 4–5 days for rats while for KETRI 3637-infected mice and rats was 5–9 and 4–12 days, respectively. Pairwise comparison between PP of mice and rats separately infected with either isolate showed no significant difference ( p  > 0.05). The PP’s of KETRI 3637-infected mice were significantly ( p  > 0.01) longer than those infected with KETRI 3439 or KETRI 3622, a trend also observed in rats. The second parasitaemic wave was more prominent in mice. Clinical signs included body weakness, dyspnoea, peri-orbital oedema and extreme emaciation which were more common in rats. Survival time for KETRI 3439 and 3622-infected groups was significantly ( p  Mastomys is a suitable model for studying pathophysiology of HAT.