PNAS https://doi.org/10.1073/pnas.1719785115 (2018).

City-living is associated with allergies in people, but disentangling all of the variables is difficult. Recently, dogs, as opposed to mice, were used as an alternative model for allergenic risk. Canines are likely better models than rodents because they share our environment as companion animals and also spontaneously develop allergies; however, they do not share all of the complexity associated with a human lifestyle. For dogs, living without other pets and in urban settings were risk factors for developing allergic conditions. These differences were also observable in the skin microbiota. This study emphasizes the need for people to make good lifestyle decisions regarding location and household size, not only for themselves, but also for their faithful friends.