Pests and Pets: Historical Dialectic

On the one hand, one of the primary reasonx why household pests (such as mice) are a problem is that they

Edit: this post probably should have a picture.

can spread infectious diseases.

On the other hand, it’s well-documented that pets (such as mice) provide substantial health benefits to their owners, both psychologically, with stress or depression, and physically, with things like blood pressure.

On the third hand, the robust trend of developed societies is towards smaller and smaller dangers from infectious diseases, with an increasing proportion of health risks coming from either psychological disaffection (at least, these are becoming more often diagnosed…) or from illnesses relating to lifestyle rather than microbes, like heart disease.

This suggests that over time, the potential health benefits of animals living in houses become more significant, while the potential health risks become less significant.

(Obviously assumptions are made here, e.g. that the comfort provided by a pet can be provided by a pest as well. But it seems that this would depend a lot on the details of interaction)