Because the destruction of tropical rainforests has led to the spread of more infectious diseases,which is true for all regions, but poverty in Africa amplifies the effects of transmission, so viruses originating in Africa can easily develop into globalized events. Infectious diseases remain one of the leading causes of human death in the 21st century, causing nearly 10 million deaths per year (about one in four), and half of all deaths in Africa are caused by infectious diseases.
In the last decade or so, the world has seen many new outbreaks of infectious diseases. At the same time, there has been a resurgence of "old killers". However, no continent has been hit harder than Africa. If you know a little bit about the origins of viruses, most of the famous emerging deadly viruses also originated in Africa, such as HIV, Ebola and Dengue. Africa's tropical climate is a breeding ground for emerging pathogens, and the environmental changes have created conditions for microbes to flourish.
How do environmental changes affect infectious diseases? These new pathogens didn't follow comets. They lurked in animals, but by destroying nature, humans unleashed them on themselves. Whether it's fever malaria or hemorrhagic Ebola, the destruction of rainforests may be partly responsible for their outbreaks in Africa. When trees are cut down, infected pools are exposed to the forest, which creates a new breeding ground for mosquitoes that carry diseases like malaria. The destruction of tropical rainforests can also lead to the loss of wildlife that protects animals from infectious diseases.
For example, coyotes, snakes, and other predators commonly prey on disease-carrying rodents. Humans kill them in their search for timber and break down natural barriers against plague and malaria. Dense forests full of birds and healthy lakes full of fish are important for mosquito control. This goes some way to explaining the resurgence of yellow fever and malaria.