Bees taught to detect Covid-19

THE fight against the coronavirus pandemic has scientists tapping an unlikely resource: the finely-tuned olfactory senses of bees.

Dutch researchers said this week they have trained honeybees to stick out their tongues when presented with the virus’s unique scent, acting as a kind of rapid test.

Although a less conventional method than lab tests, the scientists said teaching bees to diagnose the coronavirus could help fill a gap in low-income countries with limited access to more sophisticated technology, like materials for polymerase chain reaction (PCR) tests.

“Not all laboratories have that, especially in smaller-income countries,” said Wim van der Poel, a professor at Wageningen University, which led the research.

“Bees are everywhere,” he said, “and the apparatus is not very complicated.”

The scientists trained roughly 150 bees with a Pavlovian conditioning method in which they gave the insects a sugar-water solution each time they were exposed to the smell of the coronavirus.

When the bees were presented with a sample that was negative for the virus, they received no reward.

After repeatedly extending their tongues – technically called proboscises – for the sugar water, the scientists said the bees learnt to stick out their tongues for a positive sample, even with no reward offered.

Within hours, the insects were trained to identify the virus a few seconds after encountering it, the researchers said.

While the research continues, Van der Poel said the scientists believe they can achieve about a 95% accuracy rate if they use multiple insects to sniff each sample.

Their results have not yet been published or peer-reviewed.

“Our first goal was to demonstrate that we could train bees to do this, and that’s where we succeeded,” Van der Poel said.

“And now we are calculating, and we are continuing the work to see how sensitive the method is.”

The idea for the research sprang from the founders of Dutch insecttechnology start-up InsectSense, who had previously used bees to detect mineral-rich ore and landmines.

When staff realised they could also train bees to find the coronavirus, they roped in the university researchers.

Each time the scientists wanted to train a new set of bees, they used a refrigerator or the natural external temperature to cool them down and make them less active, Van der Poel said.

Then they put the bees in harnesses so they would stay still while confronted with the samples, which consist of the respiratory material from a nasal swab, mixed with chemicals.

The bees smelled samples from minks and humans, and were similarly good at identifying the virus in both situations, Van der Poel said.

InsectSense said it was working on a machine that could train multiple bees simultaneously to make the diagnoses, as well as a biochip that would use genes from the cells that bees smell with to detect the virus.

That method would circumvent the need to use live insects, which Van der Poel said might be impractical on a large scale.

“If this is going to work, it can be fast and very cheap,” Van der Poel said. “And that would be very convenient.”

A study published by the University of Pennsylvania last month suggested that dogs can detect the coronavirus with 96% accuracy.

Van der Poel said he thought scientists could more easily test samples with several bees than several dogs, given the relative ease of handling bees. In addition to identifying diseases, animals – including dogs, wasps and grasshoppers – have long been used to detect explosives.

Researchers working for the US military began to study the concept, known as “insect sniffing”, in the late 1990s. |