Pandemics and Infectious Diseases

1. Pandemics and Infectious Diseases

2. Try to guess…what are the top 10 causes of death worldwide 10. Hypertension (2% of all deaths) 9. Vehicular Accidents (2.2% of all deaths) 8. Diabetes (2.7% of all deaths) 7. Diarrhea (2.7% of all deaths) 6. HIV & AIDS (2.7% of all deaths) 5. Lung, Tracheal, & Bronchial Cancers (2.9% of all deaths) 4. Lower Respiratory Infections (5.5% of all deaths) includes pneumonia, tuberculosis, influenza, bronchitis, etc 3. COPD – Chronic Obstructive Pulmonary Disease (5.6% of all deaths) 2. Stroke (11.9% of all deaths) 1. Coronary Heart Disease (13.2% of all deaths)

3. Causes of death in the developed world • Many of the same causes, Heart Disease is still #1 • But there’s no Diarrhea in the Top 10, or HIV/AIDS, • There is Suicide, Alzheimers, Kidney Disease

4. What is “Medical Geography”? • Study of the interconnections between population, health and the environment • Cause and diffusion of disease • Provision and consumption of health care • Social construction of health • Effects of environmental change

5. Some Terms To Know • If a disease is epidemic, ….. there are numerous outbreaks and the situation gets more serious. • If a disease is pandemic, ….. this is a serious situation and it means that it has spread globally.

6. Bacterial, parasitic, or viral? • Bacterial: a disease caused by bacteria, it is alive and so can be killed by antibiotics • Viral: a disease caused by a virus, its symptoms can be alleviated but it can’t be cured, it is not “alive” so can’t be killed • Parasitic: a disease caused by a parasite (tiny bug or worm)

7. Cause and Spread of Disease • In 1854 London, England there was a Cholera outbreak where 616 people died • At the time they thought it might be spread by inhaling infected air or eating contaminated food

8. Dr. John Snow (yes, really) used a dot map to map the addresses of cholera victims and the location of water pumps they used • Discovered that most of the cholera victims lived around one pump that was contaminated • Most famous and earliest case of geography and maps being utilized to understand the spread of a disease • https://www.youtube.com/watch?v=1jlsyucUwpo

9. Disease Mapping

10. Where is Cholera today?

11. Cholera Deaths • Cholera deaths result from severe dehydration caused by diarrhea • This is treatable; in 2004 only 2.5% of cholera cases were fatal

12. Epidemiology • : the branch of medicine that deals with the incidence, distribution, and control of disease

13. Epidemiologic Transition Theory Why do some regions face health threats? • Each stage of the demographic transition model has distinctive causes of death • The leading causes of death change from infectious to degenerative types as the demographic transition occurs.

15. Epidemiologic Transition Stage 1 Death because of: • Infectious and parasitic diseases (Black Death) • Nutritional deficiencies • Death by animal attacks • Accidents • Killed by other people • High Birth Rate • High Death Rate • Slow population growth • Happens in very poor, isolated places

16. Plague • This disease has changed the course of human history • Caused by a bacteria transmitted to humans by fleas from infected rats • There are several types but the most famous is the Bubonic Plague • Named after the hard swollen “buboes” or lumps that develop near the flea bite

17. More Plague • Bubonic plague killed 60%, but some other forms of Plague killed 90% of its victims • When the rats start dying off, the fleas find human hosts • The first incident of this kind of plague was in the years 541-544 when it spread from Egypt to Europe and killed ¼ of Mediterranean Europe and helped in the downfall of the Roman Empire

18. Plague as Biological Weapon • During various Medieval wars, armies would use plague-infected bodies as biological weapons • They would use them to contaminate enemy’s water supply • Or they would catapult the bodies into the cities during a siege • During WW2 the Japanese used it on Chinese soldiers

19. Plague still exists • Today there are antibiotics and a vaccine but there are still pockets where it survives

20. River Blindness • Onchocerciasis (River Blindness): a disease caused by infection with the parasitic worm • It is the second most common cause of blindness due to infection • 17-25 million people are infected • Most infections occur in sub-Saharan Africa, although cases have also been reported in Yemen and isolated areas of Central and South America.

21. Epidemiologic Transition Stage 2 • Death caused by receding pandemics – cholera, tuberculosis, typhus, yellow fever • High birth rate • Death rate starts to drop due to advancements in healthcare and sanitation • Rapid population growth • Late 19th century Europe and America; or current Kenya, Egypt

22. 1918 Influenza outbreak • It infected 500 million people • It killed 50 - 100 million of them—3-5% of the world's population • One of the deadliest natural disasters in human history • Most flu outbreaks kill young, elderly, or already weakened patients • In contrast this flu killed mostly healthy young adults

23. Spanish Flu • To maintain morale, wartime censors minimized early reports of illness the USA and most of allied Europe • But papers were free to report the epidemic's effects in neutral Spain • This created a false impression of Spain as especially hard hit— thus the nickname

24. How Did It Spread • Modern transportation made it easier for soldiers, sailors, and travelers to spread the disease. • In the USA, the disease was first observed in January 1918 • It struck every corner of the globe • In Canada 50,000 died • http://www.youtube.com/watch?v=rbYwNOcKqqc

25. Epidemiologic Transition Stage 3 Death caused by Degenerative Diseases • Decrease in deaths from infectious diseases (vaccines) • Increase of chronic disorders associated with aging e.g. heart attacks &cancer • Death rates still dropping • Birth rates also now start to drop • Rapid growth still • Happens in places like Brazil

26. Anti-Vax leads to Measles Outbreaks • Measles was considered eliminated from the USA in 2000 • But now with the anti-vaccination movement, it’s come back • It’s extremely contagious, airborne, and can be deadly • Preventable through immunization

27. Epidemiologic Transition Stage 4 Death caused by Delayed Degenerative Diseases • Cancer and heart disease • Tobacco, alcohol, poor diet, lack of exercise • Birth rate and death rates stabilize • Slow population growth

28. Obesity

29. Epidemiological Transition Stage 5 • Death caused by new diseases, and same reasons as Stage 4 • Some infectious diseases have evolved and returned • New diseases have emerged • New strains of viruses & bacteria are drug resistant • Most people can’t afford new drugs

30. Malaria • Nearly eradicated in 1950s by spraying DDT in areas infested with the mosquito that carried the parasite. • Returned after 1963 with the evolution of DDT-resistant mosquitos

31. Smallpox • An infectious viral disease • Originally known as the "pox” or "red plague” • It killed millions in the 18th-20th centuries • It killed 20-60% of victims (80% of infected children) • After a vaccine was developed, the disease was eradicated in 1979

32. Syphilis • A bacterial infection transmitted through sexual contact • 12 million people infected in 1999, with greater than 90% of cases in the developing world • Called the ‘French disease’ or ‘the Great Pox’

33. Polio • An infectious viral disease • Often causes paralysis of the legs • One of the most dreaded childhood diseases of the 20th century • A vaccine was developed in the 1950s • Now less than a thousand people have it

35. HIV/ AIDS • Infection rates are as high as 25% in southern and eastern Africa. • In 2006 the HIV prevalence rate among pregnant women in South Africa was 29%. • By 2025 AIDS could kill 31 million people in India, 18 million in China, and 90–100 million in Africa.

36. Ebola • Ebola hemorrhagic fever (EHF): a viral hemorrhagic fever • The largest outbreak to date was the epidemic in West Africa in 2013-2016 with 11,310 deaths • It was declared no longer an emergency in March 2016 • The disease kills between 25 -90% of those infected • The virus spreads through bodily fluids

37. New Pandemics • SARS (severe acute respiratory syndrome): a viral respiratory disease • In 2002-2003, an outbreak of SARS in southern China caused an eventual 8,098 cases, resulting in 774 deaths reported in 37 countries. No cases of SARS have been reported worldwide since 2004. • H1N1(swine flu): a subtype of the influenza virus • In June 2009, the World Health Organization declared the new strain of swine-origin H1N1 as a pandemic. • This novel virus spread worldwide and had caused about 17,000 deaths by the start of 2010. In August, the World Health Organization declared the H1N1 influenza pandemic over

38. Antibiotic-resistant superbugs • These are new mutations that are immune to antibiotics • Some of the most concerning strains include CRE, MRSA, and C. difficile • Each of these superbugs are potentially fatal • Most of these strains are acquired in hospital settings

39. Barriers to Spread of Disease Natural physical barriers Human measures Immigration policy Closing international borders Isolation Hand washing Cancel public events • Mountainous areas • Extreme climate regions • Oceans

40. Play Solve the Outbreak • This is available as an app or you can just play it on the CDC (Centre for Disease Control) website • https://www.cdc.gov/mobile/applications/sto/web-app.html