Did you know that even the tiniest creatures can detect markers of illness, including cancer? From ants to worms, these animals are proving to be valuable allies in the fight against human disease.
One common ant species, Formica fusca, found throughout Europe, can be trained to detect the scent of breast cancer in urine. In a study by the University Sorbonne Paris Nord in France, the ants were taught to distinguish between the scent of urine from mice carrying human breast cancer tumors and that of healthy mice. The ants learned to seek out the cancer scent through a process called operant conditioning, where they were given a sugar reward near the cancer sample. The ants spent 20% more time with the cancerous samples.
Dogs are well-known for their cancer-detecting abilities, but did you know they can also detect infectious diseases in humans and animals, including malaria and chronic wasting disease in deer? Dogs have even been trained to screen people for COVID-19 in some schools in California and Massachusetts and at Miami Heat basketball games. In an ovarian cancer study, different dogs responded to different fragments of odors, suggesting they could detect more than one scent.
African giant pouched rats detect explosives and tuberculosis through a bouquet of odors specific to Mycobacterium tuberculosis, the bacterium that causes tuberculosis. These rats can screen over 100 patient samples in about 20 minutes, which would take a human researcher four days to accomplish. Since their inception, the rats have detected more than 23,000 cases missed by local health clinics, increasing case detection by around 50%.
Honeybees are exquisitely sensitive to scents and have been shown to be good at scenting out SARS-CoV-2, the virus that causes COVID-19. Researchers with the Wageningen Bioveterinary Research laboratory in the Netherlands trained local bees to identify scents from various samples and rewarded them with a sugary treat when they responded to COVID-positive materials. They were able to perform this action without reward over time and could check a test in just seconds.
Finally, even worms have cancer-detecting abilities. Caenorhabditis elegans, a worm-like creature approximately the size of a grain of sand grain, can detect pancreatic and breast cancer cells. In some circumstances, the worms move toward samples with cancer cells and avoid the healthy ones.
These animals detect diseases by perceiving volatile organic compounds (VOCs) in exhaled breath, sweat, urine, and blood. Diseases can change the VOCs we emit, resulting in a different odor. However, what exact chemicals the animals are smelling is unknown.
It’s clear that these animals have incredible abilities that could be harnessed to improve human and animal health. They are also relatively inexpensive and easy to maintain, making them excellent candidates for disease detection work.
So, next time you encounter ants in your kitchen, remember their extraordinary powers of perception. These animals are not just a nuisance but valuable allies in the fight against human disease. We can support this work by donating to charities like Medical Detection Dogs or APOPO, which train dogs and rats, respectively, to detect diseases.
Let’s harness the power of these incredible animals and continue to explore their potential in disease detection.