In 2016, a 70-year-old woman landed in the hospital due to a blood infection with the bacterium Capnocytophaga canimorsus, a bacterium frequently found in the canine oral cavity. The source of infection was likely her Italian greyhound. After two weeks of intensive care and broad-spectrum antibiotics, she recovered fully. The authors of this case report write that in general, the elderly are disproportionately prone to infection, due to age-related immune dysfunction and increased pet ownership. Still, the chances of picking up a bacterial infection from your pet are quite slim.

However, we also don’t know very much overall about the microbes canines carry in their mouths. Recently, a study published in PLoS ONE found that the oral microbiome of dogs is very different than the human oral microbiome. Only 16.4 percent of the microbes identified are shared between dogs and humans. Understanding the canine oral microbiome can help scientists learn about how dogs could be a potential source of pathogens and parasites and how the canine microbiome interacts with pathogens.