What lifestyle and other changes have caused the problem?
- Allergies/CIDs existed prior to 1800s – but are largely diseases of last 100 -200 years
- Accumulated data suggests
– increasing levels from the late 19th century
– rapid rise from the 1970s
- What has changed in past 2 centuries to deprive us of requisite microbial exposure?
- It seems likely that not one – but all of the following factors are involved: