The gold standard for virus detection is by quantitative polymerase chain reaction (qPCR). This requires collection of the sample, lysis (disintegration of virus structure) of the biological material, followed by rapid temperature cycles that doubles the template nucleic acids every cycle to produce a measurable fluorescent signal. Most qPCR assays take a minimum of 20 to 30 minutes to complete for a positive, and longer to confirm a negative response. This timeframe is incompatible with screening, and any attempt to make it quicker often leads to an increase in false positives. Enzyme-linked immunosorbent assays (ELISA) that target proteins are an alternative approach that can be quicker (potentially within five minutes, only requiring a single thermal incubation) but typically suffer from very high false alarms due to non-specific binding of the probe, and cannot match the sensitivity of qPCR.
There is currently no established way to detect viruses in an operationally suitable timeframe for high throughput screening, and new approaches must be developed to address this problem. But we do not have a blank canvas and cannot start from scratch. The timeframe to develop an entirely new technology is usually, at best, several years, and the world currently does not have that long unless a suitable vaccine can be developed. The best approach will be to repurpose existing screening technology to make it suitable for virus detection.
So, what are the options currently available? Well, unfortunately there are not many that are suitable. Most of the technology has been developed around explosives and narcotics detection, using ion mobility spectrometry (IMS), gas chromatography (GC) or spectroscopy (such as Raman or IR). IMS and GC (and GC-MS) require the targets to be volatile – which viruses are not – while Raman and IR do not have sufficient sensitivity or specificity for trace detection. We are not new to dealing with this problem as it is exactly the same one that we solved nearly 15 years ago when we began developing ways to rapidly detect the ingredients that make inorganic explosives. Our solution, at the University of Tasmania (UTas), was to use a different technology base – that of capillary zone electrophoresis.