Running water and sewage disposal were introduced less than a hundred years ago. Yet, we are now more susceptible to disease than 50 years ago. We are plagued with resistant bacteria, new virulent viruses and parasites. Environmental problems have resulted in many human made diseases. We are powerful and intelligent creatures with modern technology to assist us in stamping out disease, yet, pollution, holes in the ozone layer of the sky, global warming, and satellite electromagnetic beams have all contributed to a decrease in our immunity in fighting off disease.
Western medicine can no longer solve all disease.
In 430 BC, in Athens there were 200,000 inhabitants. War broke out with Sparta. Bacteria had a field day. In 1351 AD, Bubonic plague came and 30 million Europeans died. The cause was a bacteria Yersinia pestis found in the gut of fleas that lived off the blood of rodents.