A team of researchers at the University of Colorado at Boulder is developing a ‘Flu Chip’ that will aid physicians in swiftly diagnosing respiratory illnesses.
The Flu Chip will allow doctors and public health officials to differentiate between three types of influenza and other viruses that cause similar clinical symptoms, such as severe acute respiratory syndrome (SARS).
According to lead CU researcher, Professor Kathy Rowlen, influenza A viral infections have had a dramatic impact on humans, with an estimated 500,000 deaths worldwide each year and significant economic impact resulting from direct and indirect loss of productivity during infection.
‘Rapid identification of any biological pathogen, such as flu A, anthrax or SARS, requires a reliable and relatively inexpensive analytical system that can be widely manufactured and distributed,’ said Rowlen. ‘Current commercial technology for rapid identification of influenza A does not provide any genetic information and therefore cannot provide investigators at the CDC or the World Health Organisation with adequate information for managing local epidemics or worldwide pandemics.’
DNA microarrays, which are the basis for the Flu Chip, are said to represent a promising technology for accurate and relatively rapid pathogen identification based on genetic ‘signatures.’
The general structure of a DNA microarray is a well-defined arrangement of micron-sized spots on an optically flat surface, each of which contains a layer of relatively short strands of DNA designed to capture a specific genetic sequence from a sample.
Each spot, about one-thousandth of an inch across, is deposited by a robot. Patient samples can be evaluated through a fairly simple procedure called hybridisation, which is achieved by heating and slowly cooling the sample processed from a patient with the microarray.
The microarray is then developed to produce an image, said Rowlen. By knowing the identity of specific DNA segments known as oligonucleotides at any location within the array, one can determine which bits of genetic information were present in the patient sample by reading the image.
The CU team of researchers is developing the Flu Chip as an inexpensive way to swiftly screen for influenza A, the most potent strain of flu, as well as influenzas B and C, SARS and respiratory syncytial virus, which is a primary cause of respiratory illness in infants.
‘In order to address the needs in developing nations, one of our primary objectives is to create an inexpensive and field-portable test kit for respiratory illness,’ said Rowlen. ‘The goal is to provide an important new tool to the World Health Organisation for global screening of respiratory illness,’ she added.