Scientists, including one of Indian-origin, have developed a nanotechnology-based test that can quickly detect the presence of the Zika virus in the blood, an advance that may also be applicable to other emerging infectious diseases.

Currently, testing for Zika requires that a blood sample be refrigerated and shipped to a medical centre or laboratory, delaying diagnosis and possible treatment. The new test, however, relies on a protein made by the Zika virus that causes an immune response in infected individuals, which is then attached to tiny gold nanorods mounted on a piece of paper.The paper then is completely covered with tiny, protective nanocrystals. The nanocrystals allow the diagnostic nanorods to be shipped and stored without refrigeration prior to use, the researchers said.

"If an assay requires electricity and refrigeration, it defeats the purpose of developing something to use in a resource-limited setting, especially in tropical areas of the world," said Srikanth Singamaneni, Associate Professor at the Washington University in St. Louis. "We wanted to make the test immune from variations in temperature and humidity," Singamaneni added.When a drop of the patient's blood is applied on the paper mounted on the nanorods, the immunoglobulins in the blood will react with the protein if the patient has come into contact with the virus and demonstrate a colour change.

"The immunoglobulins persist in the blood for a few months, and when they come into contact with the gold nanorods, the nanorods undergo a slight colour change that can be detected with a hand-held spectrophotometer," explained Jeremiah J. Morrissey, Professor at the varsity."With this test, results will be clear before the patient leaves the clinic, allowing immediate counselling and access to treatment," he added in the paper detailed in the journal Advanced Biosystems.As other infectious diseases emerge around the world, similar strategies potentially could be used to develop tests to detect the presence of viruses that may become problematic, the researchers said.