Intestinal parasitic infections and urbanization

Abstract

About a third of the population in the cities of developing countries live in slums and shanty towns. By the year 2000 it is estimated that this number will grow to 2200 million, and by 2025 about 57% of the population in developing countries will be in urban areas. The prevalence of infections caused by Entamoeba histolytica and Giardia intestinalis and the prevalence and intensity of Ascaris lumbricoides and Trichuris trichiura infections may increase among the rural populations who are migrating to these urban and suburban settings owing to the favourable conditions for transmission. Urgent consideration should therefore be given to improving sanitation in deprived urban areas and to treating periodically these populations to reduce the worm burden, especially in school-age children.

PIP: Some of the health problems confronting millions of rural migrants to the slums, shanty towns, and squatter settlements in the urban and periurban environments of developing countries are described. According to a study, about a third of the population of the cities in developing countries live in slums and shanty towns, and, by the year 2000, perhaps as many as 2200 million people will reside in these cities. 24 of the world's cities will have at least 10 million inhabitants each, and 9 of them will be located in developing countries. About half of the 7 million inhabitants of Dhaka, Bangladesh, live in slums, and only 6% of then have access to primary education and 3% to primary health care. On the basis of current trends, by the year 2025 about 57% of the population of developing countries will be living in cities. The prevalence of infections causes by Entamoeba histolytica and Giardia intestinalis and the prevalence and intensity of Ascaris lumbricoides and Trichuris trichiura infections may increase among the rural populations who are migrating to these urban and suburban settings owing to the favorable conditions for transmission. The magnitude of the problem of providing sewerage is illustrated by considering the situation that might develop in a large metropolis like Lagos, Nigeria. According to population projections, by the year 2000 there may be an additional 1240 tons of human stool being deposited daily in the areas of Lagos where the poor people live. The installation costs of modern sewerage similar to the type found in development countries for the poor population of Lagos by the year 2000 could amount to a billion US dollars or more. Progress has been made in developing a variety of latrines for rural communities, but these may not be appropriate for slums and squatter settlements with a shortage of land for dwellings.