Studies on urban space especially within the context of urban tropical environments took a new dimension in the wake of the United Nations Conference on the Environment and Development held in Rio in 1992. Geographical or related studies, which have treated this notion in the African context, have generally stuck to the existence of myriad problems perceived as constraints to city life such as difficulties related to housing, insufficient supply of potable water, poor drainage and waste disposal, urban transport difficulty, and all types of pollutions.
However, to limit urban space in Africa only to these problems does not seem to constitute a firm scientific research objective, because this urban space is a social structure that, in its functioning, influences the life of the city dweller. For the reason that sufficient attention has been centered on the functioning of these tropical cities as living organisms where human beings subsist in interdependence with one another, we therefore, in line with several earlier writers, expand on this question by introducing the issue of persistence of numerous infectious diseases and parasites studied in sub-Saharan Africa.1
Today, the situation is deteriorating as shown by the example of diarrheal infection. It occupies the third position among the most deadly infectious diseases in the world, affecting all ages, with 2.2 million deaths in 1998. In terms of disability-adjusted life years, diarrhea occupied the second position in 1998, with 73 million cases, after acute respiratory infections (83 million cases).2 It showed in the same year that the probability of contracting diarrhea in sub-Saharan Africa was over 39.1 percent compared with 7.2 percent in the developed countries. The two rates point to the gravity of the plague at the global level, principally in the developing countries.
It thus seems restrictive to talk of space and environment in an equatorial and urban milieu without being burdened by the health problems that are commonplace there. According to the World Health Organization (WHO), "Health is a fundamental human right and a social and universal end indispensable for the satisfaction of man's basic needs and quality of life, and [End Page 680] thus must be extended to everybody."3 In view of health being at the center of human life, the study of these health problems is very important especially for urban populations, whose health situation is deteriorating and becoming precarious because of a fall in their living standards. Better still, since these populations are unavoidably important for development policy and strategy, we think that the issue of their "physical and mental well-being" is no longer the responsibility of health professionals alone. At a time when pessimistic views—pushed by the failure of the "Health for all by the year 2000" target and by the ravages of HIV/AIDS—are predicting a health catastrophe in Africa, we think that a multidisciplinary approach to the predicament is in order. The contribution of geography to the "global and spatial health needs of the population, their health behaviors and factors, which contribute to, or militate against their health, is incontestable."4 This may help in fostering a better understanding of the health issues in cities and thus permit the implementation of appropriate measures. We have accorded this importance to the study of health (by studying diarrheal diseases) in urban equatorial environments and specifically in Yaoundé, Cameroon.
Diarrheas: Cosmopolitan Diseases Indicating Poor Conditions of Living and Hygiene
The term diarrhea is indeed current, however, the diarrhea disease dates back to historic times. The term comes from the Greek word dia, which signifies "flowing from all parts."5 Hippocrates in his writings (ca. 460–ca. 377 BC) gave this description: "abundant liquid...