With infection, there is usually history of exposure to the infectious agent or traumatic injury to the affected region. (cvm.ncsu.edu)
In multiple cat environments, keeping cats as healthy as possible and minimizing exposure to infectious agents lessens the likelihood of cats» developing FIP. (chai-online.org)
The Hygiene Hypothesis states that when children lack early exposure to infectious agents, parasites, and symbiotic microorganisms like normal gut flora such as would naturally occur in a rural or farm environment, they are much more likely to suffer from autoimmune disorders such as allergies or asthma. (thehealthyhomeeconomist.com)