Once a person is affected by a dengue virus, the platelets can no longer âactivateâ itself. So whenever there is damage, the platelets cannot form the mesh structure and the blood flows out of the vessel. As blood flows out, so does the platelets. This causes the platelet count to fall drastically. The blood that flows out causes internal. and external bleeding and leads to a haemorrhage.
The people of Egypt used the regular event of the River Nile flood to their advantage. Until 1970, the Nile had flooded every Spring as the mountain snows melted. This flooding of the flat land (floodplains) alongside the river enriched the soils leaving behind rich silt in which crops could be grown.
The blessings of the Nile were many, but they did not come without some costs. A low flood could lead to famine, and too high a flood could destroy dikes and other irrigation works. Even a 2-meter drop in the river's flood level could leave as much as a third of the floodplain unwatered. [7].