An old tool that has been used for decades to determine which chemicals are in foods, the human body and pharmaceuticals could now be used to see if a mosquito is carrying the Zika virus.

The microcephaly-causing virus has spread by mosquito into many new countries in recent years, including Fiji, Samoa and Tonga. A major challenge in monitoring the situation has been the lack of fast, affordable tests.

Currently, genetic material is analysed for the virus using the reverse transcription polymerase chain reaction (RT-qPCR). But a study published in Science Advances has found that near-infrared spectroscopy (NIRS) predicts Zika with between 94.2 and 99.3 per cent accuracy. NIRS simply involves shining a light at the head and thorax of the mosquito to read the chemical compounds within. It’s 18 times faster and 116 times cheaper than RT-qPCR, with no need for dissections or reagents.