Dengue is spread by the Aedes aegypti mosquito

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[MONTEVIDEO] A cheap, simple, non-invasive test for dengue that eliminates the need to collect blood from patients has been developed by researchers in Singapore.

The researchers hope it could yield a commercial test as simple as a home-based pregnancy test kit.

The need for a blood sample is one of the main limitations of dengue diagnosis tools, particularly in children, say the authors, and the "tendency to forgo a dengue blood test is high". A non-invasive method could potentially improve surveillance and early detection of cases, which in turn could translate to prompt control efforts.

The new test collects saliva from patients with suspected dengue. The overall sensitivity of the test was 70 per cent in the first three days after the onset of fever, and 93 per cent between four and eight days after fever onset.

The test, reported in the June edition of PLoS Neglected Tropical Diseases, is not the first of its kind. However, according to Lee-Ching Ng, lead author of the study and director of the Environmental Health Institute at the National Environment Agency, Singapore, it addresses two important issues.

"We have an assay that eliminates the competition between dengue-specific and non-dengue specific antibodies present in saliva and, thus, improved the sensitivity of such tests," Ng told SciDev.Net.

"We also used a saliva collection method that allowed for the collection of actively secreted saliva. Instead of getting patients to spit into a container, or allowing saliva to dribble out into a container, we used a sterile swab to systematically scrub the cheeks, stimulating the salivary glands to produce saliva.

"This assay has the potential to substitute all blood-based dengue assays commercially available on the market," said Ng. "We hope that it will be available at least at the same costs as those assays, or even cheaper, so that it can be widely accessible."

Ng said that the assay is undergoing multi-centre evaluation. "We are also seeking partners for commercialisation. We hope to work towards a point-of-care assay that is similar to a pregnancy test kit."

Link to full paper