New system to quickly detect flu viruses

The system was developed by Dr Yong Poovorawan, Kamol Suwannakarn and Sunchai Payungporn of the Centre of Excellence in Clinical Virology, Faculty of Medicine, Chulalongkorn Univeristy.

According to team leader Dr Yong Poohworawan, who is also a virological expert, this technique uses molecular diagnosis to detect the virus genes. The team has developed the one-step Reverse Transcription-Polymerase Chain Reaction (RT-PCR) as a rapid and specific method for identifying the H5N1 and H6 influenza A virus.

He said this technique could detect and identify both human and avian flu viruses at the same time, which not only saves time but also money.

Yong explained that influenza viruses are classified into types A, B and C, based on the antigenic differences in their nucleo- and matrix proteins. The A and B types are main agents of human acute respiratory disease and affecting infants, the elderly and individuals with compromised cardiac, pulmonary or immune functions.

Most influenza pandemics are associated with the Type-A virus, which represents the most widespread human and animal pathogen. This type can be further classified into subtypes based on the antigenic variation of the hemagglutinin (HA) and neuraminidase (NA) glycoprotein on the surface of viral particles. To date, 16 HA and nine NA subtypes of Type-A viruses have been detected in wild birds and poultry across the world

As viruses of all subtypes have been isolated from aquatic birds, they are considered a reservoir of Type-A for other animal species. The number of viral subtypes found in mammals is limited, with the most common subtype of Type-A virus affecting humans being H1N1, H2N2, and H3N2. Though human infections from additional Type-A subtypes, including H5N1, H7N7, H7N3 and H9N2, have been reported over the past few years.

To mitigate an influenza outbreak, Yong said early and rapid detection of infectious strains and subtypes in each patient is required.

The technique has been approved and published by two international journals - "The Journal of Virological Methods" and "Tohoku Journal of Japan" - and hospitals can access details of the system in their websites.