21 October 2003

A University of Queensland researcher has developed a cheaper, faster and more reliable test for two severe yet common childhood viral diseases.

The real-time Polymerase Chain Reaction (PCR) test slashes diagnostic times from days to a matter of hours and promises to revolutionise worldwide laboratory procedures.

Senior researcher with UQ's Clinical Medical Virology Centre (the Sir Albert Sakzewski Virus Research Centre) based in the Royal Children's Hospital Dr Ian Mackay developed the test in response to outbreaks of human enteroviruses (HEV) and human metapneumovirus (hMPV) infection in Melbourne and Perth in 1986 and 1999 respectively, and Queensland during 2001.

Enterovirus 71 (EV71) can cause hand, foot and mouth disease, encephalitis, aseptic meningitis and paralysis in children.

hMPV causes serious respiratory tract disease in children and adults and until Dr Mackay's test, it was estimated 40 percent of cases went undetected because of the limitations of conventional diagnostic testing procedures.

In 78 percent of cases during the 2001 outbreak, children were admitted to hospital for between one and 14 days with 12 cases requiring oxygen therapy.

Dr Mackay's test allows the amplification of tiny amounts of RNA up to a billion-fold to enable easy detection and subsequent molecular manipulation. It also provides a far cheaper alternative to traditional culture methods.

He said while PCR had been available since the 1980s, real-time PCR was a more recent and significant improvement to the technique.

"Fluorescent emissions can be collected from a closed tube at any stage of the amplification process. This eliminates the risk of contamination to the laboratory environment," he said.

"Real-time PCR brings many benefits to the diagnostic laboratory such as increased speed (reducing assay times from days to hours), reliability (good reproducibility) and specificity (the inclusion of an oligonucleotide probe to 'check' that the PCR product is what we expect it to be).

"Also checking whether a microbe responds to anti-microbial drugs; the speed at which it grows both inside and outside its host; and the ability to rapidly diagnose new and emerging microbes such as hMPV by monitoring viral 'load' (amount or level) from patient specimens from different age groups and disease states."

Dr Mackay developed the test as part of his PhD with the Centre and has already shared his discovery with laboratories across the world through scientific papers and conference presentations.

More information about these viruses and others can be found on his website Virology Down Under at: www.uq.edu.au/vdu

Media contact: Dr Ian Mackay (telephone 07 3636 1620 (lab), 07 3636 1619 (office), email ian.mackay@uq.edu.au) or Brad Turner at UQ Communications (telephone 07 3365 2659 or email b.turner@uq.edu.au).