Review: The impact of changing human environment and climate change on emerging and re-emerging parasitic diseases

Abstract

Emerging infectious and parasitic diseases are the newly identified and previously unknown infections of public health importance while re-emerging diseases, on the other hand, are those that had been brought under control but reappear and
increase in alarming rate. The current population explosion, with the consequent urban expansion, or growth of urban slums, and squatter settlements have led to rapid deterioration of human environment. The infrastructural facilities of these settlements
already limited in their capacities fail to provide adequate housing, sanitation, health-care and other public utilities. These together with ignorance and human behaviour result in serious changes to our environment to the advantage of these diseases.
Some well-intended socioe-conomic development projects, as a result of inadequate ecological assessment and evaluation, have after completion caused untold public health problems. The resulting changes either aggravate the prevalence of some
parasitic diseases [re-emergence] or introduce the diseases into new areas by providing new and permanent habitats for the parasites and their vectors as well as disease transmission. The changes in worldís ecosystem are now being joined by
human-induced changes to trigger out-breaks of emerging and re-emerging diseases. These changes are linked with human population explosion, rapid international travels, changes in food handling and processing as well as deteriorating public
health infrastructure, and drug resistance. The impact of human-induced climate change through industrialization with the consequent depletion of the ozone layer of the environment is now observed to compromise the sustainability of human
development as it threatens the ecological support system on which life depends in addition to encouraging the emergence and re-emergence of vector-borne parasitic diseases. The public health and epidemiological implications of these are discussed.

Keywords: previously unknown infections, ecosystem, human-induced climate change, re-emergence of parasitic diseases, vector-borne diseases.

Nigerian Journal of Parasitology Vol. 28 (2) 2007: pp. 135-145