Pathogenicity of trypanosomes in relation to 1 drug sensitivity: comparative studies between a drug-sensitive and drug-resistant Trypanosoma congolense strain in murine-and bovine model [post]

2020 unpublished
Indiscriminate exposure of Trypanosoma congolense and other trypanosomes to trypanocides have led to emergence of resistant strains, which increasingly undermine the control efforts against tsetse transmitted animal trypanosomosis. Despite the increasing trend of resistance, no studies have conducted to assess whether or not drug sensitivity affects the pathogenicity of T. congolense and other predominant species. Methods: We compared the pathogenicity of two strains of trypanosomes:
more » ... nosomes: drug-sensitive Trypanosoma congolense -Mikese and drug-resistant T. congolense Mbagala. These strains were isolated from cattle at Mikese, Morogoro region and Mbagala, Dar es Salaam region, Tanzania, respectively. Experimental mice and cattle were infected with either tryapnosomes and monitored for rectal temperature, prepatent period, parasitemia, packed cell volume (PCV), survival and clinical manifestations. Drug sensitivity status of either strains was re-confirmed before pathogenicity testing. Results: Mean rectal temperature was higher in mice infected with T. congolense -sensitive strain (p=0.049, 95% CI= 0.003-1.13). Mean prepatent period of resistant strain in mice and cattle was shorter than that of sensitive strain. The mean level of parasitemia was significantly higher in resistant-(7.5±0.8) than in sensitive-strain (6.5±0.8) (p<0.001, 95% CI= -1.28 to -0.68). Mice infected with resistant strain were relatively dull and lethargic compared to those infected with sensitive strain. The decline PCV was higher in cattle infected with sensitive-strain than resistantstrain (p=0.041, 95% CI, -6.97 to -0.17). Conclusion: Pathogenicity of the two Trypanosoma congolense strains varied significantly across host species. The resistant strain was highly pathogenic in mice and less so in cattle. Contrarily, the sensitive strain was highly pathogenic to cattle and less so to mice. As such, this study emphasizes variations on the pathways by which different trypanosomes act upon the host; thus warranting subsequent studies using large number of experimental animals, preferentially cattle, in view of reflecting the field situation. 12
doi:10.21203/rs.3.rs-17414/v1 fatcat:feeg2gpw6bfo7lcdphny4b2rqu