Class of 2019D Research

Demographic evolution, climatic change and economical development that happened in West Africa during the XXth century had a lot of consequences on human settlement and landscape. These changes have in turn an impact on the pathogenic system of human and animal trypanosomoses. Since last century, the northern tsetse distribution limit has shifted towards the south, probably due to a decrease in rainfall combined to the impact of human pressure. Sleeping sickness (SS) foci have also shifted from the savannah areas (where there is no more SS) to the forest and mangrove areas of West Africa, but animal trypanosomoses are still present in savannah. We show a decrease of tsetse of the morsitans group as a result of an increase of human densities. On the opposite, tsetse species like Glossina palpalis adapt to high human densities and are found in the biggest urban centres of West Africa. There is a need to promote multidisciplinary studies on this demographic-climatic-vector borne disease topic, especially in Africa to be able to define future areas of presence/absence of these diseases in order to help continental plans of control that have recently begun.

It is appalling to know that at one point of time nearly 14.8 billion acre of land was covered with forests. This size has over the years come down to a mere 8.6 billion. Deforestation and the effects of deforestation have taken place in a high scale over the last 50 years. Deforestation in rainforests has primarily been due to cattle grazing, timber industry, and agriculture. Deforestation has taken place in Central America for raising beef to satisfy ever growing human needs. The tropical forests of Central America are facing a huge price for it. The level of carbon dioxide released in the atmosphere is high due to rainforest deforestation. In such cases the trees do not have the ability to absorb the rainfall followed by preventing soil erosion. The next scene is flooding and daily siltation of rivers occurring at such areas. Did you know that rainforests once depleted do not have a chance to restore? Hence, once humans began depleting rainforests it should be likely that they are gone for the rest of this life.

mpacts of Deforestation: Biodiversity Impacts Although tropical forests cover only about 7 percent of the Earth’s dry land, they probably harbor about half of all species on Earth. Many species are so specialized to microhabitats within the forest that they can only be found in small areas. Their specialization makes them vulnerable to extinction. In addition to the species lost when an area is totally deforested, the plants and animals in the fragments of forest that remain also become increasingly vulnerable, sometimes even committed, to extinction. The edges of the fragments dry out and are buffeted by hot winds; mature rainforest trees often die standing at the margins. Cascading changes in the types of trees, plants, and insects that can survive in the fragments rapidly reduces biodiversity in the forest that remains. People may disagree about whether the extinction of other species through human action is an ethical issue, but there is little doubt about the practical problems that extinction poses.

Smog hanging over cities is the most familiar and obvious form of air pollution. But there are different kinds of pollution—some visible, some invisible—that contribute to global warming. Generally any substance that people introduce into the atmosphere that has damaging effects on living things and the environment is considered air pollution.Carbon dioxide, a greenhouse gas, is the main pollutant that is warming Earth. Though living things emit carbon dioxide when they breathe, carbon dioxide is widely considered to be a pollutant when associated with cars, planes, power plants, and other human activities that involve the burning of fossil fuels such as gasoline and natural gas. In the past 150 years, such activities have pumped enough carbon dioxide into the atmosphere to raise its levels higher than they have been for hundreds of thousands of years.Other greenhouse gases include methane—which comes from such sources as swamps and gas emitted by livestock—and chlorofluorocarbons (CFCs), which were used in refrigerants and aerosol propellants until they were banned because of their deteriorating effect on Earth's ozone layer.