Response of outbred albino mice to concomitant Heligmosomoides bakeri, Plasmodium berghei and Trypanosoma brucei infections.

To investigate the response of mice to concomitant infections with Trypanosoma brucei (Tb), Plasmodium berghei (Pb) and Heligmosomoides bakeri (Hb) infections. Each group of 6 mice was either infected with Pb + Tb + Hb, Pb + Tb, Pb + Hb, Tb + Hb, Pb, Tb, Hb or remained as uninfected controls. Hb infected mice each received 200 infective larvae (L3) of Hb orally, Tb infected mice each received 2 × 10-6 organisms through the intraperitoneal route while Pb infected mice received 1 × 10-5 parasitized red blood cells through the intraperitoneal route. PCV, body weights (BW), faecal egg counts (FEC), Tb parasitaemia, Pb parasitaemia, clinical signs and worm burdens (WB) were determined. FEC were highest in Pb + Tb + Hb and least in Hb group and the difference was significant (P < 0.05). WB was significantly higher in mice with concurrent infections. PCV of infected mice was lower than that of uninfected controls and the difference was significant between Pb + Tb + Hb infected and uninfected controls. The difference in weight loss was significant between Pb + Tb + Hb infected and controls. Mortalities occurred in Pb + Tb + Hb, Tb + Hb and Pb + Hb infected mice. Mortalities and low PCV and low BW were indications that concomitant infections were more pathogenic to the mice than single infections, pathogenicity increasing with increasing number of parasite species involved.