Dogs can smell things at concentrations of one part in a trillion—equal to a single drop in a pond the size of 20 Olympic swimming pools. That ability is put to good use by human beings. Trained dogs can sniff out explosives and drugs, even tracking missing people. They can also detect (发现) illnesses, including cancer, malaria, Parkinson's disease and COVID-19, before obvious symptoms appear. A study published in 2019,for example, suggested that trained dogs detect (发现) illnesses, including cancer, malaria, Parkinson's disease and COVID-19, before obvious symptoms appear. A study published in 2019, for example, suggested that trained dogs were able, 97% of the time, to identify blood samples taken from patients with lung cancer.
Training dogs, however, takes time. Trainers must be paid. The animals themselves get tired and bored. Dogs are not, then, a practical answer to the question of how to detect illness quickly. But fruit flies might be. Unlike dogs, they are cheap and disposable--and their senses are just as good. Along with technology tailored to their talents, they could provide economical and easy ways of detecting cancer, and also offer an alternative to laboratory tests for COVID that might be welcome in countries with limited budgets.
Giovanni Galizia is one leading researcher of the University of Konstanz, in Germany. Fruit flies smell things using their feelers, and Dr Galizia has genetically modified (改变) his flies. When the flies get the smell of the cells with illness, a change in their brain activity can be seen under a microscope. With the help of machine learning, Dr Galizia can recognize the patterns to detect illness.
Whether this idea will come to fruition remains to be seen. Medical regulators will have to be convinced that what may seem wacky at first glance is actually practical. But doctors have been encouraged to use animals' noses to assist diagnosis (诊断) since ancient times. Having a little assistance from fruit flies might be no bad thing.
