Although it may not be obvious to most people, there can be no doubt that this has increased the chances of diseases spreading. For example, it is the development of forest areas which has enabled dengue fever, which originated in the jungle, to evolve into an "urban virus."
原來處於原始叢林裡的登革熱病毒，就是因為人類的開發，轉而進化為「都市型病毒」。