Parasitic diseases are usually common in rainforest parts of the world (the tropical and subtropical regions) because such environment favour the existence of the causative agents of such infections. For example, malaria caused by Plasmodium species is more prevalent in tropical and subtropical regions than in temperate regions where the environmental condition is cold and cannot favour the development of the parasite. Below are some of the reasons for the disparity in parasitic diseases that occur in tropical and temperate regions of the globe.
- The tropical (hot) regions are usually ecologically relatively less stable than the temperate (cold) regions. This imbalance gives parasites the occasion to disturb and disrupt the ecological imbalance between man and host environment.
- Most parasitic diseases (malaria and guinea worm infection) have either been totally eradicated or contained in temperate regions.
- Due to the usually high rainfall experienced in the tropics than in most temperate regions, there is low level of public health improvements in most tropical areas especially in countries that have not yet put in place a sustainable environmental and pollution control measures.
- Most parasites complete their life cycles in arthropods which find the tropics (that are usually warm and humid) to be most suitable and favourable for their fast breeding and development.
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