A group of Australian scientists and physicists from the University of Wisconsin-Milwaukee (UWM) has employed state-of-the-art military hardware in a method that quickly identifies malaria parasites in blood samples as small as a single cell.
Researchers at Australia’s Monash University and the University of Melbourne came to Wisconsin to use unique imaging equipment created by UWM professor Carol Hirschmugl in order to investigate strategies for earlier diagnosis of the disease.
The scientists say the novel idea, published July 14 in the journal Analyst, could set a new gold standard for malaria testing. One of the most deadly diseases on the planet, malaria kills about a million people a year.
Hirschmugl’s equipment incorporates a special detector known as a Focal Plane Array (FPA), originally developed for anti-tank heat-seeking missiles.
Like the sensor in a large mega-pixel camera, the FPA detector recognizes pixels and is sensitive to the infrared spectrum. Hirschmugl has used it as part of equipment she developed, called Infrared Environmental Imaging (IRENI).
“With the detector we essentially get a mega-pixel camera for infrared, rather than visible light,” she says. “It is key to my system and the whole reason I built IRENI.”
‘Seeing’ with frequencies
The tool yields high-definition pictures of the kinds of molecules in a sample with exceptional clarity and speed.
In IRENI, the FPA detector is paired with a synchrotron as the camera’s light source. In a synchrotron, streams of speeding electrons emit continuous light across the entire electromagnetic spectrum so that researchers can note where certain wavelengths are most readily absorbed by the test material.
The malaria test was conducted using IRENI equipment at the Synchrotron Radiation Center at UW-Madison where light in the invisible mid-infrared range was absorbed at millions of locations in the blood sample.
Taken together, the data form a high-definition image which, once reassembled by a computer program, produces a “hyper-spectral map,” guiding scientists to the exact location of the target – those cells where the infrared signature produced by the parasites’ fatty acids appeared.
“Rather than having to look everywhere in a sample, this method points you to which cell is infected with the parasite and at which stage of the disease,” says Hirschmugl.
Early detection difficult
Lead researcher Bayden Wood, associate professor of biochemistry at Monash University, specializes in imaging biomolecules with a technique called Fourier Transform Infrared (FTIR) spectroscopy, which provides information on how they vibrate. He says a test that can catch malaria at its early stages is critical to reduce mortality and prevent the overuse of anti-malarial drugs.
The disease is often spotted only after the parasites have developed and multiplied in the body.
This test could make an impact if it results in large-scale screening to identify carriers of the malaria parasite who do not display the disease’s classic fever-type symptoms, says Leann Tilley, professor of biochemistry and molecular biology at the University of Melbourne.
If those carriers are treated before symptoms appear, it will keep the disease from spreading quickly within a community.
In the next phase of research Wood’s team will work with Professor Patcharee Jearanaikoon from the Khon Kaen University in Thailand to test the new technology in hospital clinics.
For Hirschmugl, the test demonstrated the medical applications of IRENI, though she acknowledges that synchrotron-based imaging is not practical for use in developing countries where malaria poses the biggest threat.
“The hope is to keep pushing the commercial technology to improve,” she says. “The quality of what is available commercially now has improved because of our research so far.”