Project Lead(s): Zablon Njiru
Issue
Human trypanosomiasis (Chaga’s disease and sleeping sickness) are fatal diseases endemic in rural Latin America and Africa, where over 150 million people are at risk of infection.
In addition, the disease form in livestock causes ~$7.5 billion in annual losses in Sub-Saharan Africa and Asia.
Simple and definitive diagnostic tests for the three forms of trypanosomiasis are lacking.
Solution
The project aimed to develop a simple, field-based, diagnostic test that would be capable of detecting all pathogenic trypanosomes in vectors, animals and, if possible, humans responsible for causing three forms of trypanosomasis (sleeping sickness, Chaga’s disease and animal disease).
This project set out to develop a lyophilized nucleic acid-based test that would fill this need.
The assay had to be simple to perform, stable in hot, humid field conditions, have a short turnaround time to results and require minimal equipment.
The team developed a dried (lyophilized) master mix capable of detecting all pathogenic trypanosomes responsible for causing three forms of trypanosomiasis.
Mixing the master mix with primers forms the Tryps Rapid test.
To perform a test, the master mix and primers are reconstituted with double distilled water. A specially prepared sample is added and the recipe incubated, using a unit capable of maintaining temperatures of 55oC
The results are visually inspected by colour change or using a dipstick.
Outcome
Testing showed unequivocal detection of target DNA, with an analytical sensitivity superior to PCR tests available for detection of pathogens in vectors and animals.
The throughput from sample preparation to result was approximately >62 tests per three hours/per person, with time to results of one hour. The master mix is stable at 40°C and 70% humidity for three months, so refrigeration is not required. The master mix also showed potential use in detection of malaria and Buruli ulcer disease. Nominally-trained technicians can perform the test after two days of training.
Analysis of archived DNA previously prepared from tsetse flies and animal samples show that the Tryp Rapid test is superior to available PCR tests.
Work on the project has not yet been published because the intellectual property application is pending.