Do you know someone who is sick? Your own smell can give it

Odors surround us, providing hints on many aspects of personal identity, including health status. The Monell Center's research now broadens the scope and meaning of personal smells as a source of information about an individual's health. A new paper in the newspaper with free access Scientific reports reveals that the body odors of healthy animals sharing an environment with sick animals become like the smells of sick animals.

The results suggest that the olfactory signals associated with the disease can cause biological changes in healthy individuals, which may impact social contacts and perhaps even the spread of the disease.

"Odor exposure of sick people can trigger protective or preparatory responses to their social partners to minimize the risk of imminent infection," said lead author of the study, Stephanie Gervasi, Ph.D., chemical ecologist at Monell.

Monell's earlier work had demonstrated that inflammation resulted in changes in body odor, suggesting that odors activated by immunity could signal the presence of a risk of disease (or of possible contagion) to other members of a species.

In the present study, the researchers injected mice with lipopolysaccharide (LPS), a non-infectious bacterial toxin that causes inflammation, activation of the immune system, and other symptoms associated with the disease. The "sick" animals that received an injection of LPS were then housed in the same cages as the healthy animals.

Bioassay results from "sniffer" mice formed to differentiate urine odors from animals injected with LPS and healthy animals indicated that healthy partners of sick animals were more sensitive than healthy animals. healthy animals.

A parallel analysis using statistical predictive modeling of urinary odor compounds identified by analytical chemistry confirmed the results of behavioral bioassays: the models were more likely to classify odorous compounds from healthy healthy mice than healthy ones when healthy mice were housed with sick animals.

Similar results were obtained when the study was repeated with diseased and healthy animals physically separated by a perforated septum. The score allowed odors to circulate, strongly suggesting that changes in healthy mice did not result from a transfer of physical odors.

The combined results reveal that the body odors of healthy animals can change in the presence of odor-based disease signals.

"This work not only shows that smells report disease, but that they can have significant effects on the individuals who detect them," said Gary Beauchamp, behavioral biologist at Monell, one of the authors Main article. "This is a remarkable information transfer by olfaction that specifically alters physiology and could play a role in disease transfer in individuals of many species."

Bruce Kimball, Ph.D., research chemist at the National Wildlife Research Center of the USDA (NWRC) based in Monell and also lead author, notes that the study results could be particularly relevant to wild animal populations. "This knowledge that healthy animals can emit odors associated with the disease can inform our efforts to use body odor to understand how pathogens are transmitted in an animal population," he said. declared.

Explore more:
Changes in body odor after vaccination

More information:
Scientific reports (2018). www.nature.com/articles/s41598-018-32619-4