Faster diagnosis may help curb outbreaks of deadly diseases – ScienceDaily

A new tool can quickly and reliably determine the presence of the Ebola virus in blood samples, according to a study by researchers at Washington University School of Medicine in St. Louis and colleagues at other institutions.

The technology, which uses so-called micro-optical resonators, could be developed into a rapid diagnostic test for the deadly Ebola virus disease, which kills up to 89% of those infected. The Ebola virus, since its discovery in 1976, has caused dozens of outbreaks, mostly in Central and West Africa. Most notable was the outbreak that began in 2014 and killed more than 11,000 people in Guinea, Sierra Leone and Liberia. In the United States, the virus has caused 11 cases and two deaths. Rapid early diagnosis can help public health workers track the spread of the virus and implement strategies to reduce outbreaks.

The study — which also included researchers from the University of Michigan, Ann Arbor, and Integrated Biotherapeutics, a biotechnology company — was published June 8 in Cell Reporting Methods.

“Anytime you can diagnose infection earlier, you can allocate healthcare resources more efficiently and promote better outcomes for the individual and society,” said co-first author Abraham Qavi, MD, a postdoctoral researcher at the University of Washington. “Using a biomarker of Ebola infection, we have shown that we can detect Ebola infection in the first critical days after infection. A few days makes a huge difference in terms of providing medical care to the people who need it and breaking the cycle of transmission.”

The Ebola virus is transmitted through contact with bodily fluids. It causes fever, body aches, diarrhea and bleeding – non-specific symptoms that can easily be confused with another viral infection or malaria. In recent years, effective Ebola vaccines and treatments have been developed, but they are not widely available. Instead, health officials control the deadly virus by containing the outbreak. The strategy is based on rapid identification of infected persons and prevention of transmission by encouraging caregivers to wear protective clothing.

Qavi previously worked with Ryan C. Bailey, Ph.D., Robert A. Gregg Professor of Chemistry at the University of Michigan and co-author of this paper, to co-develop micro-optical resonators, a type of whisper-exposure mode device. used for molecular detection. The name comes from the Whispering Gallery in St Paul’s Cathedral in London. A whisper on a walkway in the dome above the nave can be clearly heard more than 100 feet away because the sound waves increase in amplitude as they bounce around the ring wall. Eighteenth century builders created a giant demonstration of the principle of acoustic resonance, where sound waves increase in amplitude if they interact in exactly the right way. The same phenomenon occurs with light waves on a much smaller scale.

When Ravi joined the lab of co-author Gaia K. Applying technology to create a better diagnostic test for Ebola. Qavi collaborated with Bailey, co-first author Krista Meserve, a graduate student in Bailey’s lab, and co-author Lan Yang, PhD, Edwin H. and Florence G. Skinner Professor of Electrical and Systems Engineering at the McKelvey School of the University of Washington. Engineering, to develop a tool that can detect trace amounts of Ebola-related molecules in blood samples using micro-resonators.

“We trap the light in the resonators and use the resonance to boost and enhance our signal,” Qavi said. “By observing where this resonance wavelength occurs, we can tell how much of the molecule we have.”

The key was finding the right molecule. Current diagnostic tests detect the virus’s genetic material or glycoprotein – a protein covered in sugar – produced by the virus. But it is not reliable until the virus has multiplied to high levels in the body, a process that can take days. Co-senior author Frederic Holtzberg, PhD, vice president of manufacturing and bioanalytics at Integrated Biotherapeutics, has developed a highly sensitive antibody capable of detecting virus-soluble glycoprotein at low levels.

The researchers incorporated the antibody into their devices and tested it using blood from infected animals. They found that their method could detect glycoprotein as early as or before the most sensitive test for viral genetic material. Importantly, the technology also allowed them to determine the amount of viral glycoprotein in the blood. The higher the level, the worse off the injured animals. Moreover, the test only took 40 minutes from start to finish.

“Looking at this data, we can say, ‘If you are above these levels, your chance of surviving is low; if you are below that, your chance of surviving is high’,” Qavi said. “We still have to validate this in affected individuals, but if it continues, clinicians can use this information to design treatment plans for individual patients and allocate rare drugs to patients who are most likely to benefit from them.

“We’ve shown the basic science work,” he added. “Now it’s just a matter of miniaturizing the devices and bringing them into the field.”

This study was supported by the National Institutes of Health (NIH), grant numbers CA009547, P01AI120943, R01AI123926, R01AI141591 and R01AI107056.


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