In 2009, there was an outbreak of a highly contagious influenza strain called H1N1. According to the World Health Organization, there were 8,480 officially reported cases and 72 deaths across 39 countries within a month of the first case surfacing. Although H1N1 ultimately caused relatively few deaths, the event shows that highly virulent influenza strains could spread rapidly around the world and underscores the importance of identifying infected patients quickly.
Conventional influenza diagnoses are often conducted at centralized clinical diagnosis laboratories. The procedures are complex and the diagnosis, even when performed by skilled operators, can take several hours. Mo-Huang Li and Jackie Y. Ying at the A*STAR Institute of Bioengineering and Nanotechnology and co-workers have now developed a fully automated portable desktop system for rapidly diagnosing infectious diseases and successfully applied it for the diagnosis of influenza.
The desktop system has several advantages over existing methods. It is fully automated and does not need to be assisted by highly skilled operators. This makes it potentially suitable for use at immigration checkpoints, train stations, airports and outpatient clinics, rather than having to depend on centralized clinical establishments. Its all-in-one design should also make it cheap to manufacture, and reduces the risks of hardware contamination and accidental viral exposure.
The researchers have shown experimentally that their system can efficiently detect influenza viruses in samples that contain as few as 100 viral particles per milliliter. It does so by applying the real-time polymerase chain reaction (RT-PCR) process to amplify the viral RNA before molecular analysis.
All the operator has to do is to take a swab from the patient, add a solution, and inject it with a syringe needle into a disposable self-contained cartridge (pictured) holding all of the necessary RT-PCR reactants. The entire preparation and diagnostic process is thereafter fully automated and takes just 2.5 hours to complete. The sealed cartridge containing all of the waste products can then be safely disposed of.
The researchers have successfully used their automated system to type and subtype seasonal H1N1 influenza viruses, and showed that the system has comparable sensitivity to that of conventional diagnostic methods. In principle, the system could be used to diagnose other infectious diseases caused by viruses that have many subtypes leading to similar patient symptoms.
“We hope that the use of our portable device will aid the decentralized diagnosis of infectious diseases and alleviate the burden on healthcare personnel in the diagnosis of an overwhelming number of suspect cases,” says Li.
The A*STAR-affiliated researchers contributing to this research are from the Institute of Bioengineering and Nanotechnology.