In the present study, a LAMP test was designed from the serum resistance-associated (SRA) gene of Trypanosoma brucei rhodesiense, the cause of the acute form of African sleeping sickness, and used to detect parasite DNA from processed and heat-treated infected blood samples.
The human serum resistance-associated (SRA) gene was identified in 28 (80%) of the 35 T.b. rhodesiense trypanosomes from parasitologically confirmed sleeping sickness cases, using the primers designed by Radwanska and in 27 (77.1%) of the same 35 T.b. rhodesiense trypanosomes using the primers designed by Gibson.However, about 20% of the 35 T.b. rhodesiense trypanosomes could not be detected by SRA-polymerase chain reaction (PCR) even when an aliquot of the first PCR was used in the second PCR, indicating that the gene may be absent in those trypanosomes or the trypanosomes could be having another variant of SRA not detectable by these primers since three variants of SRA genes have so far been identified or the amount of trypanosomal DNA extracted from infected blood was too low to be detected.
Blood from 231 patients with sleeping sickness in central Uganda and from 91 patients with sleeping sickness in northwest Uganda and south Sudan were screened for T b rhodesiense (detection of SRA gene) and T b gambiense (detection of TgsGP gene).
Detection of the SRA gene could provide the basis for a simple diagnostic test to enable targeted control of T b rhodesiense in the domestic livestock reservoir, thereby reducing the public-health burden of sleeping sickness in east Africa.