Epidemiology and public health - A brief notes.ppt
- 1. EPIDEMIOLOGY
- 2. • Epidemiology is the branch of medicine which deals with the incidence, distribution and possible control of diseases and other factors relating to health. • Study and analysis of the distribution (who, when and where) and determinants of health and disease conditions in defined populations. • Epidemiology has helped develop methodology used in clinical research, public health studies and to a lesser extent, basic research in the biological sciences.
- 3. • Epidemiologists help with study design, collection and statistical analysis of data, amend interpretation and dissemination of results. • It is the cornerstone method of public health research and helps inform policy decisions and evidence – based medicine by identifying risk factors for disease and targets for preventive medicine.
- 4. Major areas of epidemiological study include disease causation, transmission, outbreak investigation, disease surveillance, forensic epidemiology, occupational epidemiology, screening, biomonitoring and comparisons of treatment effects such as in clinical trials. Epidemiologists rely on other scientific disciplines like biology to better understand disease processes, statistics to make efficient use of the data and draw appropriate conclusions, social sciences to better understand proximate and distal causes and engineering for exposure assessment. The health hazards of industrial and agricultural chemicals and the toxic waste created by their production and use, also pose increasing problems.
- 5. • Environmental health comprises those aspects of human health, including quality of life, that are determined by physical, biological, social and psychosocial factors in the environment. • It also refers to the theory and practice of assessing, correcting, controlling and preventing those factors in the environment that can potentially affect adversely the health of present and future generations. • Episodes of poisoning because of industrial errors have been catastrophic.
- 6. 1. Bhopal gas tragedy: the Union Carbide gas leak 2. Chernobyl: Russian nuclear power plant explosion 3. Seveso: Italian dioxin crisis 4. 1952 London smog disaster 5. Major oil spills of the 20th and 21st century 6. Love Canal chemical waster dump 7. Baia Mare cyanide spill 8. European BSE crisis 9. Spanish waste water spill 10. Three Mile Island near nuclear disaster
- 7. Bhopal Tragedy: • The Bhopal disaster, also referred to as the Bhopal gas tragedy, was a gas leak incident on the night of 2–3 December 1984 at the Union Carbide India Limited (UCIL) pesticide plant in Bhopal, Madhya Pradesh, India. • A leak of methyl isocyanate gas and other chemicals from the plant resulted in the exposure of hundreds of thousands of people. • In Bhopal 3,500 people died and 2,00,000 were injured when isocyanate was released from a pesticide factory into the surrounding slums.
- 8. Chernobyl accident • It was occurred on 26th April 1986 at the Chernobyl nuclear power plant in Ukraine. • Five million people in the Ukraine, Belarus and the Russian Federation were exposed to ionising radiation. • An increase in the incidence of childhood thyroid cancer has been one of the major health consequences of the accident, particularly in Belarus. • Ultimately it is estimated that the after effects of this nuclear disaster will cause 6,600 deaths from cancer and leukaemia.
- 9. Seveso disaster, Italy The Seveso disaster was an industrial accident that occurred around 12:37 pm on July 10, 1976, in a small chemical manufacturing plant approximately 20 kilometres (12 mi) north of Milan in the Lombardy region of Italy. It resulted in the highest known exposure to 2,3,7,8-tetrachlorodibenzo-p- dioxin (TCDD) in residential populations • A toxic cloud containing dioxins, which are very potent cancer-causing chemicals, was released into the atmosphere and spread across the nearby densely populated city of Seveso. • Exposure to such carcinogens does not result in short-term health problems, but the effects may be expressed decades later.
- 10. Within days a total of 3,300 animals, mostly poultry and rabbits, were found dead. 15 children were quickly hospitalised with skin inflammation. 1,600 people of all ages had been examined and 447 were found to suffer from skin lesions or chloracne
- 11. 1952 London smog disaster • The Great Smog of London or Great Smog of 1952, was a severe air-pollution event that affected the British capital of London in early December 1952. A period of cold weather, combined with an anticyclone and windless conditions, collected airborne pollutants—mostly arising from the use of coal—to form a thick layer of smog over the city. It lasted from Friday, 5 December to Tuesday, 9 December 1952 and then dispersed quickly when the weather changed. • The unusual cold in London in the winter of 1952-1953 caused additional coal combustion and many people travelled only by car, which caused the occurrence of a combination of black soot, sticky particles of tar and gaseous sulphur dioxide.
- 12. • The smog episode killed approximately 12,000 people, mainly children, elderly people and people suffering from chronic respiratory or cardiac disease. • The London smog disaster resulted in the introduction of the first Clean Air Act, 1956.
- 13. Major oil spills of the 20th and 21st century • At the end of the 20th Century and the beginning of the 21st Century there have been oil spills all over the world, caused either by naval accidents or during major wars. • It is impossible to determine which of these oil spills had the most severe consequences for its environment. • Examples: - 1985 ARCO Anchorage spills 5.690 barrels of oil near the coast of Washington - 1986 unknown oil spill reaches the coast of Georgia and is later appointed to the Amazon Vulture tanker - 1989 Aragon tanker spills 175.000 barrels of oil near Madeira, Portugal - 1990 tanker American Trader grounds near Huntington Beach, California and spills 9458 barrels of oil - 1990 Cibro Savannah tanker catches fire and spills 481 square meters of oil
- 14. - 1990 Jupiter tanker catches fire in Bay City, Mexico and causes oil spill - 1990 Mega Borg tanker catches fire and spills 19.000 square meters of oil near Galveston, Texas - 1991 tanker Bahia Paraiso spills 3.774 barrels of oil near Palmer Station, Antarctica - 1992 Greek tanker Aegean Sea spills 70.000 ton oil near Galicia - 1993 Bouchard B155 tanker spills 1.270 square meters of fuel oil after collision with 2 ships - 1996 Liberian tanker Sea Empress spills 147.000 ton oil near Wales - 1999 Maltese tanker Erika spills 30.000 ton oil near Brittany - 2001 tanker Jessica spills 900 ton oil near the Galapagos Isles - 2002 Bahamese Prestige spills oil near Galicia.
- 15. Love Canal tragedy • One of the most famous and important examples of groundwater pollution in the U.S. is the Love Canal tragedy in Niagara Falls, New York. It is important because the pollution disaster at Love Canal, along with similar pollution calamities at that time. • The Love Canal tragedy helped to create Superfund, a federal program instituted in 1980 and designed to identify and clean up the worst of the hazardous chemical waste sites in the U.S. • Thus created Superfund has analyzed tens of thousands of hazardous waste sites in the U.S. and cleaned up hundreds of the worst ones. Nevertheless, over 1,000 major hazardous waste sites with a significant risk to human health or the environment are still in the process of being cleaned.
- 16. Baia Mare cyanide spill • The 2000 Baia Mare cyanide spill was a leak of cyanide near Baia Mare, Romania, into the Some’ River ș by the gold mining company Aurul, a joint-venture of the Australian company Esmeralda Exploration and the Romanian government. • The polluted waters eventually reached the Tisza and then the Danube, killing large numbers of fish in Hungary and Romania. The spill has been called the worst environmental disaster in Europe since the Chernobyl disaster
- 17. BSE - a crisis in Europe and worldwide • In the late 1980s and early 1990s Bovine Spongiform Encephalopathy (BSE) in cattle became first a European and later a global animal health and food safety crisis with major implications also on the trade and export of animals and derived products. During the epidemic, more than 1,85,000 BSE cases in cattle were confirmed in the European Union. At the height of the crisis, consumer confidence in the food chain was at an all time low. In response to this, the European Union implemented a new, comprehensive regulatory framework to improve EU food safety, ensure a high level of consumer protection and restore and maintain confidence in the EU food supply.
- 18. Spanish waste water spill • On April 25, 1998 the dam of the mining residual tank of a pyrite mine in Aznalcollar, Spain suffered a rupture, releasing sludge and contaminated wastewater. The wastewater entered the Guadiamar River, polluting the river with heavy metals such as cadmium, lead, zinc and copper. • It affected an area of 4.634 hectares, contaminating 2.703 hectares with sludge and 1.931 with acidic water. • The river pollution caused cultivation lands and forests to be affected. Harvests were no longer fit for consumption, causing financial problems for farmers in the area. Major fish mortality occurred and birds died as a result of consumption of polluted fish. It took one whole month for the river water to recover to its original state.
- 19. Three Mile Island near nuclear disaster • At approximately 4:00 a.m. on March 28, 1979 the main feed water pumps in the non-nuclear cooling system of reactor 2 of the Three Mile Island nuclear power plant near Harrisburg, Pennsylvania failed. • This caused cooling water to drain away from the reactor resulting in partial melting of the reactor core. Operator errors, a stuck valve, faulty sensors and design errors together resulted in a release of approximately one thousandth as much radiation as during the Chernobyl explosion.
- 20. Natural Environmental Disasters Global epidemics (The Plague, Spanish Flu and AIDS) The Bangladesh arsenic crisis 2004 Asian earthquake and tsunami Hurricane Mitch Izmit: the 1999 Turkish earthquakes 1953 Dutch flood disaster Brazil: the 1998 Roraima wildfires Philippines: the Mount Pinatubo volcanic eruption 1925 Ellington, Missouri tornado The Beijing and Queensland dust storms