ENVIRONMENTAL studies show that health problems in many countries emanate primarily from lack of access to essential resources — sufficient and clean water, enough food, appropriate shelter and healthy air. In fact, most infectious diseases are “environmental” in origin, as specific environmental conditions increase the biological organisms’ ability to thrive and spread. This is especially true with acute respiratory infections, which are linked to poor conditions within the housing environment, including overcrowding, poor sanitation and pollution.

Be that as it may, the most formidable adversaries that humans encounter remain to be microorganisms — viruses and bacteria. Years of concerted efforts reveal that while it is very difficult to eradicate microbial threats, it is possible to live in balance with them.