Project Lead(s): Isaac Bogoch
Issue
Typhoid fever remains one of the most important infectious diseases in the developing world.
The most recent global estimates for the burden of typhoid suggest that Salmonella typhi and S. Paratyphi together account for 26 million cases and more than 200,000 deaths per year.
Despite its limited sensitivity, blood culture is considered to be the best available test for routine diagnosis but requires laboratory capacity, including electricity and trained personnel, which are not available in many rural settings.
Solution
The study team sought to validate a simple, electricity-free procedure for isolating typhoid fever from blood with the use of an incubator and demonstrating its equivalence to conventional culture testing.
Implemented in Nepal, the project involved screening 3,057 individuals who presented to four clinics with fever of at least three days’ duration. Samples collected from rural clinics were processed with the electricity-free device. Bottles were placed into an insulated container together with sealed packets containing 1-tetradecanol, a chemical that, upon heating in a hot water bath or via sunlight, maintains temperature of 38C for prolonged periods. Bottles are inspected daily for de-colouration of a CO2 sensor, which indicates bacterial growth.
Outcome
Of the 3,057 individuals, 128 bacterial cultures were shown to be positive, many with the novel, electricity-free device. The findings were validated using conventional microscopy in a hospital-based laboratory.
Seventy of the 128 (55%) cases were diagnosed as typhoid fever, with the remainder being other bacterial infections.
All people were treated as per local guidelines and at the clinician’s judgement.
The team will not be applying for Phase II Transition To Scale funding, since this device is extremely inexpensive and the commercialization potential is unclear.