A new study has found that trained dogs can identify people with COVID-19, even when those people show no signs of the illness.

In the study, researchers collected a small amount of sweat from the underarm area of 177 test subjects. Some were infected with COVID-19 and some had tested negative for the coronavirus. The dogs then smelled the sweat samples and tried to identify infected people from non-infected people.

Early results from the study were published December 10 in PLoS One. The results were based on data gathered in March of this year.

The researchers have since confirmed these early findings in additional tests. That is what study leader Dominique Grandjean told the Reuters news agency. He is with the Alfort Veterinary School in France.

The dogs, researchers said, were able to correctly identify infected individuals 76 to 100 percent of the time. Also, the dogs were able to rule out infection 92 to 99 percent of the time.

And, Grandjean adds, they were able to do these things quickly.

"It takes one tenth of a second," he said, "for a trained dog to say 'yes' or 'no.'"

Training the dogs requires three to eight weeks. The length of time depends on whether the dog is already trained for smell detection.

The study involved six detection dogs: three explosive detection dogs, one search and rescue dog, and two colon cancer detection dogs.

The research was carried out in two places: Paris, France and Beirut, Lebanon.

It involved 177 people. Of those 177, 95 tested positive for COVID-19 and had signs of sickness. The other 82 test subjects were COVID-19 negative and had no signs of sickness.

COVID-19-detecting dogs, Grandjean explained, have already been used in airports in the United Arab Emirates. The UAE government plans to help other countries use trained dogs, as well.

On December 16, the UAE and the International K9 Working Group Against COVID-19 held an online event explaining the use of these trained dogs. Representatives from 25 countries attended the workshop.

I'm Anna Matteo.

Nancy Lapid reported this story for Reuters News Agency. Anna Matteo adapted it for VOA Learning English. Ashley Thompson was the editor.

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sweat – n. the fluid excreted from the sweat glands of the skin : sweat – v. to produce a clear liquid from your skin when you are hot or nervous

negative – adj. not showing the presence of what is looked for or suspected to be present

sample – n. a small amount of something that gives you information about the thing it was taken from

data – n. facts or information used usually to calculate, analyze, or plan something

odor – n. a particular smell

veterinary – adj. relating to the medical care and treatment of animals

detect – v. to discover or determine the existence, presence, or fact of : detection – n. the act or process of discovering, finding, or noticing something

conduct – v. to plan and do (something, such as an activity)

positive – adj. showing the presence of what is looked for or suspected to be present