This July 29, 2020 news item on Nanowerk features research from Brazil,
A new class of nanosensor developed in Brazil could more accurately identify dengue and Zika infections, a task that is complicated by their genetic similarities and which can result in misdiagnosis.
The technique uses gold nanoparticles and can “observe” viruses at the atomic level, according to a study published in Scientific Reports (“Nanosensors based on LSPR are able to serologically differentiate dengue from Zika infections”).
Belonging to the Flavivirus genus in the Flaviviridae family, Zika and dengue viruses share more than 50 per cent similarity in their amino acid sequence. Both viruses are spread by mosquitos and can have long-term side effects. The Flaviviridae virus family was named after the yellow fever virus and comes from the Latin word for golden, or yellow, in colour.
“Diagnosing [dengue virus] infections is a high priority in countries affected by annual epidemics of dengue fever. The correct diagnostic is essential for patient managing and prognostic as there are no specific antiviral drugs to treat the infection,” the authors say.
More than 1.8 million people are suspected to have been infected with dengue so far this year in the Americas, with 4000 severe cases and almost 700 deaths, the Pan American Health Organization says. The annual global average is estimated to be between 100 million and 400 million dengue infections, according to the World Health Organization.
Flávio Fonseca, study co-author and researcher at the Federal University of Minas Gerais, tells SciDev.Net it is almost impossible to differentiate between dengue and Zika viruses.
“A serologic test that detects antibodies against dengue also captures Zika-generated antibodies. We call it cross-reactivity,” he says.
Meghie Rodrigues’ July 29, 2020 article for SciDev.net, which originated the news item, delves further into the work,
Co-author and virologist, Maurício Nogueira, tells SciDev.Net that avoiding cross-reactivity is crucial because “dengue is a disease that kills — and can do so quickly if the right diagnosis is not made. As for Zika, it offers risks for foetuses to develop microcephaly, and we can’t let pregnant women spend seven or eight months wondering whether they have the virus or not.”
There is also no specific antiviral treatment for Zika and the search for a vaccine is ongoing.
Virus differentiation is important to accurately measure the real impact of both diseases on public health. The most widely used blood test, the enzyme-linked immunosorbent assay (ELISA), is limited in its ability to tell the difference between the viruses, the authors say.
As dengue has four variations, known as serotypes, the team created four different nanoparticles and covered each of them with a different dengue protein. They applied ELISA serum and a blood sample. The researchers found that sample antibodies bound with the viruses’ proteins, changing the pattern of electrons on the gold nanoparticle surface.
Should you check out Rodrigues’ entire article, you might want to take some time to explore SciDev.net to find science news from countries that don’t often get the coverage they should.
Here’s a link to and a citation for the researchers’ paper,
Nanosensors based on LSPR are able to serologically differentiate dengue from Zika infections by Alice F. Versiani, Estefânia M. N. Martins, Lidia M. Andrade, Laura Cox, Glauco C. Pereira, Edel F. Barbosa-Stancioli, Mauricio L. Nogueira, Luiz O. Ladeira & Flávio G. da Fonseca. Scientific Reports volume 10, Article number: 11302 (2020) DOI: https://doi.org/10.1038/s41598-020-68357-9 Published: 09 July 2020
This paper is open access.