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Monica Staniek

Who sniffs the sniffers? Electronic nose takes a whiff of dogs to spot deadly disease

Dogs are champs at smelling, a quality that has been harnessed to sniff out mines and may one day be used to diagnose cancer. But now it’s an electronic nose’s turn to sniff the pooches.

The reason: “visceral leishmaniasis,” a disease spread by the sand fly parasite that can cause weight loss, enlarged organs, and fever in people and weight loss, diarrhea, and skin problems in dogs. The number of human cases has doubled in Brazil since 1990, causing several thousand deaths a year.

Now, public health officials use a time-consuming, two-part test to identify infected dogs as part of their effort to reduce parasite populations. To see whether an “eNose” would work better, researchers collected blood and hair samples (pictured) from 16 dogs known to carry the parasite and 185 other dogs. Hair from infected dogs smells different from the hair of uninfected dogs. The handheld device contains sensors that send different electrical signals depending on the chemical compositions of odors. Water-filled bags of hair were heated and then samples of the air in the bag were blown across the eNose.

The eNose picked up leishmaniasis infections 95% of the time, the team reported last week in a preprint on bioRxiv. Further tests and a sturdier, more customized eNose are needed though before eNose takes to the streets as a tool for curbing the number of infected dogs and reducing infections in people, the researchers note. But if it can work on dogs, it can also work to quickly detect infections in humans, they predict.