Rapid sensitive typhoid diagnostic
Oxford researchers based in Vietnam have identified a combination Salmonella typhi biomarkers, which provide a high level of sensitivity and specificity for the rapid diagnosis of typhoid fever using blood sera. A previously performed proteomic analysis identified a ‘signature’ of potential biomarkers during active typhoid infection. Several of these proteins were systematically chosen by the researchers to assess their diagnostic potential.
Proof of concept data shows:
- Several of the biomarkers Life-threatening in infected individuals
- A combination of biomarkers (with the largest elevations) resulted in improved diagnostic capacity – higher levels of sensitivity and specificity in comparison with pre-existing rapid diagnostic tests
In addition to providing a more accurate diagnosis, these biomarkers may also be suitable candidates for a vaccine.
The typhoid biomarkers may be detected by any suitable quantitative or qualitative method, e.g. enzyme-linked immunosorbent assays, western blot and immunoassays.
- Life-threatening bacterial infection endemic in areas with poor sanitation/limited access to clean water, e.g. South/South East Asia & Sub-Saharan Africa.
- Approximately 21 million typhoid cases annually, resulting in 220,000 deaths worldwide (WHO).
- Symptoms include fever, nausea and muscle aches, often indistinguishable from other febrile diseases.
- Delayed treatment increases the risk of life-threatening complications, e.g. sepsis.
- Diagnosis of typhoid is a persistent challenge – due to lack of reliable gold standard test and low sensitivity of current rapid diagnostic tests.
- Only occurs in humans, meaning eradication is possible – the need for a more accurate rapid diagnostic approach to assess disease burden, to design/ implement strategies e.g. vaccination programmes/ treatment.
- The global increase in S. Typhi due to a rise in resistance to antimicrobials intensifies demand for rapid and accurate typhoid diagnosis.
- The current gold standard is blood-culture conformation – this has limited sensitivity and can take several days.
- This method is also restricted to labs with adequate equipment and training – therefore diagnosis is further limited due to the lack of microbiology facilities in developed countries/ primary care or out of hours clinics in developed countries.
- Current, rapid diagnostic tests using blood sera have a low sensitivity and specificity.
- High demand for the replacement rapid blood sera diagnostic test with a higher sensitivity and specificity, accessible to the developing world.
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