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.
More than two miles long at its crest, the massive $1 billion dam ended the cycle of flood and drought in the Nile River region, and exploited a tremendous source of renewable energy, but had a controversial environmental impact. A dam was completed at Aswan, 500 miles south of Cairo, in 1902. The first Aswan dam provided valuable irrigation during droughts but could not hold back the annual flood of the mighty Nile River.