Download Agricultural Expansion - Geography - Lecture Slides and more Slides Geology in PDF only on Docsity! Lecture 21 : New Infectious Diseases (2) Overview Underlying Causes 1. Population Growth 2. Globalisation Direct Causes 1. Urbanisation 2. Agricultural Expansion 3. Ecological Changes 4. Water Pollution 5. Global Warming 6. Ozone Hole 7. Public Health Deficiencies 8. War 9. Transport Docsity.com Population Increase • The world's population increased from 1.5 to 6 billion during the 20th century. By 2050 it may rise to 10 billion. • This has numerous knock-on effects. Docsity.com
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\ _ Manilla, Phillipines
Expansion Into New Areas • Population pressure is forcing people to colonise new areas, especially tropical forests. • Two thirds of all the species of life on earth live in the rain forests. • Most have long-established symbiotic relationships with micro organisms. • If the host population is disrupted, humans may become the new host, possibly with devastating effects (cf. Marburg, Ebola). Docsity.com Docsity.com Water Pollution • Pollution from sewage and nitrogen and phosphorus fertilisers causes eutrophication. • Algae consume oxygen, threatening other lifeforms. • Algae host bacteria and viruses, which exchange DNA to create new strains. • Algae in Sea of Bengal home to El Tor cholera vibrio which are ‘activated’ in freshwater river estuaries. • Cholera in algae in Sea of Bengal mutated to more threatening O139 strain. Docsity.com North Island, New Zealand Docsity.com Docsity.com Ozone Hole • Ozone layer in upper atmosphere is being depleted by chlorofluorocarbon (CFC) gases. • More of the Sun’s UV is getting through. • UV kills plankton, food source for fish. • UV kills cyanobacteria, essential for rice to grow. • UV increases risks of cancer, especially skin cancer. • UV intensifies mutations in plant life and algae microbes, increasing the risks of new ‘super bugs’. Docsity.com Public Health Deficiencies • Public health in Third World countries is under-resourced due to poverty. • Do not have the resources to adequately provide clean water, process sewage, eradicate vectors, provide vaccines, etc. • Even in developed countries public health is under- resourced relative to therapeutic medicine. Docsity.com War • Wars often result in collapse of public health. • STDs common due to rape. • HIV infection in Africa in 1980s tended to correspond to conflict zones, with knock-on implications for malaria and tuberculosis. • Wars cause mass population movements. • Refugee camps often very unhealthy. Docsity.com
