At least 233 species of bacteria, viruses and more live on or inside both humans and dogs.
That’s one finding from a study that matched animals with their known microbes and drew connections between species with similar microbial crews. The diagram below, published September 15 in Scientific Data, is a social network of species that resembles a vibrant tangle of yarn.
Each dot is an animal species; the creatures are clumped into colored groups such as light blue for fish and yellow for birds. Humans have the largest dot because they host at least 1,600 different microbes. The distance between dots and the lines connecting them indicate that many human microbes also reside in dogs, pigs and cattle.
Domesticated animals live beside humans, so the microbial overlap isn’t surprising, says study coauthor Maya Wardeh, a computational biologist at the University of Liverpool in England. Yet humans share microbes with fish and fall victim to Cryptosporidium fayeri, a diarrhea-inducing parasite that also infects the eastern gray kangaroo.
Wardeh and colleagues say that scientists can use the information to study how various diseases originate and jump between species.