Other factors that have also contributed to the spread of infectious diseases include the chaos of warfare, widespread malnutrition in developing countries, lack of clean water, poor sanitation, rapid international travel, and global climate change.
تبيّن ان سهولة التكيّف المذهلة التي تبديها الجراثيم العادية مشكلة رئيسية ،‏ مشكلة لا يجري توقعها عموما .‏