I just passed through Paris en route to a conference in Belgium, and was reminded of a topic that comes up occasionally: pets in restaurants. While "dining with dogs" is a common site in many areas of Europe, it is rare in North America. I periodically get asked about the risks associated with having pets (usually dogs) in restaurants, and unfortunately there isn’t a clear answer.
Overall, the infectious disease risks associated with having "Rover" in a restaurant should be very low. Dogs don’t emit some intangible "aura of infection," so just having them in the vicinity while people are eating is not a problem. Microorganisms have to make it from the dog’s body to a person (and usually into their mouth) to cause disease. We don’t have many concerns about airborne spread of diseases from dogs to people. In reality, simply having a dog in a restaurant should be less risk than having people in the restaurant (since people can transmit some infections to each other over short distances by coughing and sneezing). But for this to be true, people still have to handle their dogs properly, meaning people who touch a dog should wash their hands before eating, and restaurant staff should not touch any dogs in the restaurant at all.
Does this mean we should be allowing dogs in all restaurants? Not necessarily. The biggest weakness of even the most logical infection control measures is lack of compliance – people who break the "rules". For example, would people actually minimize contact with the dog and wash their hands? Would food servers really stay away from them? Would all dogs be adequately trained never to bite, scratch, jump up or behave inappropriately in a busy restaurant environment? Furthermore, people with allergies to pets and fear of dogs need to be considered.
In the end, most dogs probably would not cause a problem in most restaurants around most people… but "most" is not "all". Clearly, this is not a straightforward issue, and there are logical arguments on both sides.