(n.) The science of health; hygiene.

aerial infection airborne infection carrier communicability contagion contagiousness contamination cryptogenic infection direct infection droplet infection dust infection hand infection health physics hygiene hygienics indirect infection infection infectiousness mental hygiene phytogenic infection preventive dentistry preventive medicine primary infection prophylactic psychology prophylactodontia prophylaxis public health pyogenic infection sanitation secondary infection subclinical infection taint vector virus waterborne infection zoogenic infection