New light-based tool could cut cost of spotting viral infections Premium

Detecting viral infections in cells using light-based method for early intervention and prevention of outbreaks.

Viruses infect plants, animals, and humans. A virus’ spread from animals to humans could unleash pandemics like COVID-19 — significant public health crises with considerable economic and social fallout. To nip such infections in the bud, public health researchers have advocated the ‘One Health’ approach: monitoring and protecting plant, animal, environment, and human health in an integrated fashion.

Quick, easy, and cost-effective methods of detecting viral infections can go a long way in ensuring this outcome. Recently, researchers from Harvard University, Cambridge, and Jiangsu University, Zhenjiang, reported developing one such tool: it can detect if cells have been infected by a virus using only light and some knowledge of high-school physics.

Their paper was published in the journal Science Advances in March this year.

A viral infection can stress cells and change their shapes, sizes, and features. As the infection gains the upper hand and the body becomes ‘diseased’, the changes become more stark.

The researchers behind the new study translated these cellular changes into patterns that could be used to say if a cell had been infected. They infected cells from a pig’s testicles with pseudorabies virus, shone light on them through a microscope, and tracked how changes in the cells distorted the light.

The researchers recorded these distortions at different points of time so that the light data mimicked a progressing viral infection. Then they compared these distortions with those in light that had been shone through healthy cells. They finally reported that the difference between the two light patterns represented a ‘fingerprint’ of virus-infected cells.

The distortion in question referred to diffraction patterns. Diffraction is the tendency of light waves to spread out after they pass through narrow openings or around small objects. Once this diffracted light reaches, say, a wall, it renders a pattern of alternating light and dark rings or stripes around a dark centre.