Faster diagnosis can help curb deadly outbreaks – ScienceDaily

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

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

The study, which includes researchers from the University of Michigan, Ann Arbor and biotechnology company Integrated Biotherapeutics, was published June 8 in Methods for cell reports.

“Whenever you can diagnose an infection earlier, you can allocate health resources more efficiently and promote better outcomes for the individual and the community,” said co-author Abraham Cavi, MD, PhD, researcher at University of Washington. “Using a biomarker for Ebola infection, we have shown that we can detect Ebola infection in the crucial early days after infection. Several days are very different in terms of providing people with the medical care they need and breaking the transmission cycle. “

The Ebola virus is transmitted by contact with body fluids. It causes fever, body aches, diarrhea and bleeding – non-specific symptoms that can easily be mistaken for other viral infections or malaria. Vaccines and effective therapies for Ebola have been developed in recent years, but they are not widely available. Instead, health officials control the deadly virus by limiting outbreaks. The strategy relies on the rapid identification of infected people and the prevention of transmission by encouraging those caring for them to wear protective equipment.

Cavi has previously worked with Ryan C. Bailey, PhD, Robert A. Greg, Professor of Chemistry at the University of Michigan and co-author of this paper, to co-develop optical micro-ring resonators, a type of whispering gallery mode device. used for molecular detection. The name comes from the Whispering Gallery at St Paul’s Cathedral in London. A whisper uttered on a path in the dome above the nave can be heard clearly at more than 100 feet, because the sound waves increase in amplitude as they bounce around the round wall. 18th-century builders accidentally constructed a giant demonstration of the principle of acoustic resonance, in which 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 Cavi joined the lab of senior author Gaia K. Amarasinghe, PhD, an Ebola expert and professor of pathology and immunology and professor of biochemistry and molecular biophysics and molecular microbiology at the University of Washington, they decided to apply the technology to create better diagnostic test for Ebola. Cavi has partnered with Bailey, co-author Christa Messerv, a graduate student at Bailey’s lab, and co-author Dr. Lan Young, professor of electrical engineering and systems engineering at Edwin H. and Florence G. Skinner at the McKelvey School of Engineering in Washington to develop an instrument that can detect small amounts of Ebola-related molecules in blood samples using micro-ring resonators.

“We capture light in resonators and use resonance to improve and amplify our signal,” Cavi said. “By observing where this resonant wavelength occurs, we can tell how many of the molecule we have.”

The key was finding the right molecule. Current diagnostic tests detect the genetic material of the virus or glycoprotein – a protein coated with sugar – produced by the virus. But they are not reliable until the virus multiplies to high levels in the body, a process that can take days. Co-author Frederick Holtsberg, Ph.D., vice president of manufacturing and bioanalytics at Integrated Biotherapeutics, has developed a highly sensitive antibody capable of detecting viral soluble glycoprotein at low levels.

The researchers included the antibody in their device and tested it with blood from infected animals. They found that their technique could detect glycoprotein sooner or later than the most sensitive test for viral genetic material. Importantly, the technology allows them to quantify the amount of viral glycoprotein in the blood. The higher the level, the worse the infected animals do. In addition, the test took only 40 minutes to complete.

“Looking at these data, we can say, ‘If you are above these levels, your chances of survival are low; if you’re under it, your chances of survival are high, “Cavi said. “We still need to confirm this in infected people, but if it persists, doctors could use this information to tailor treatment plans to individual patients and distribute scarce medicines to patients who are most likely to benefit.

“We have shown the fundamental scientific work,” he added. “Now it’s just a matter of miniaturizing the devices and putting them in 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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