Cities and Emerging or Re-Emerging Diseases in the XXIst Century

The world’s urban population in 1996 is around 2.6 billion people, two thirds of whom live in the South. Urban-dwellers have multiplied more than four-fold over the last 50 years and now represent about 45 percent of the world’s total population. Cities, by concentrating people, increase the possibilities for transmission of infectious diseases. Where there is inadequate provision for water, sanitation, and garbage collection, disease-causing agents - or the vectors or animal hosts on which they rely - can proliferate. The emergence of new infectious diseases and the resurgence of other infectious diseases makes achieving healthy cities more difficult as health care systems prove unable to cope, or as the disease-causing agents or their vectors develop a resistance to public health measures. Without good management, cities become dangerous and unhealthy places.