Clinical and pathological characterization of Blood stream forms and cerebrospinal fluid T. b. rhodesiense trypanosomes isolated from a patient using rabbits.

Abstract

Clinical and pathological characterisation of blood stream (BSF) and cerebrospinal fluid (CSF) forms of Trypanosoma brucei rhodesiense trypanosome isolated from a sleeping sickness patient were investigated in rabbits. The study aimed at investigating whether there is any significant difference in clinical and pathological presentation in rabbits infected by the two forms of trypanosomes. Each form of parasite was inoculated into five rabbits at 10⁴ trypanosomes/ml while five rabbits were used as un-infected controls. Parasitaemia development, body temperature, packed cell volume (PCV), body weight, food and water intake, heartbeat and respiration were monitored daily for 30 days post infection when the experiment was terminated. Pathological changes were evaluated following euthanasia. All the infected rabbits became parasitaemic 6 days post infection (dpi) and the parasitaemia levels were significantly higher (p=0.01) for the BSF than the CSF infected rabbits. No significant difference was observed in heartbeat, respiration, food and water intake as well as PCV. However, CSF infected rabbits had a significantly (p=0.01) higher body temperature and weights than BSF infected rabbits. There was no major difference in the clinical manifestation of the disease caused by the two forms of parasite. However, temporary paralysis was observed around the left side of the neck in one rabbit infected with CSF trypanosomes whereas mucoid stool with the presence of amoeba cysts were observed in the rabbits infected with the BSF trypanosomes. The spleen weights of CSF infected rabbits was heavier (3.59 ± 1.13 grams) than the BSF infected rabbits (2.92± 0.78 grams). The proportions of monocytes were significantly higher (p<0.05) in the CSF infected rabbits while neutrophils proportions were significantly higher (p<0.05) in the BSF infected rabbits. The rest of the haematological changes were not significantly different. Results from this study demonstrate that BSF trypanosomes appeared relatively more virulent than the CSF trypanosomes. It would be important to carry out similar studies using a higher number of both BSF and CSF trypanosomes isolated from the same patient and different patients to authenticate this observation.