1. INFECTIOUS DISEASE EPIDEMIOLOGY Instructors: Iman Ramadan, MD King Abdulaziz University Mary C. Smith Fawzi, ScD Harvard University

2. http://www.worldbank.org/depweb/english/modules/social/life/chart1.html Life expectancy at birth,1968 and 1998

3. WHAT ARE FACTORS RELATED TO THIS RISE IN LIFE EXPECTANCY ? http://www.worldbank.org/depweb/english/modules/social/life/chart1.html

4. WHAT ARE FACTORS RELATED TO THIS RISE IN LIFE EXPECTANCY ?  Nutritional status  Safe drinking water  Sanitation  Basic health care services http://www.worldbank.org/depweb/english/modules/social/life/chart1.html

5. UNICEF State of the World’s Children Report, 2008

6. http://www.worldbank.org/depweb/english/modules/social/life/chart2.html INFANT MORTALITY RATE, 1980 AND 1998 (DEATHS PER 1,000 LIVE BIRTHS)

7. CAUSES OF INFANT MORTALITY  Pneumonia and flu  Diarrheal disease, e.g. cholera  Malaria  Diphtheria  Measles  Polio  Tetanus  Typhoid  Tuberculosis  Pertussis / Whooping cough  Infants with malnutrition at greatest risk http://www.worldbank.org/depweb/english/modules/social/life/print.html

8. CHANGES IN LIFE EXPECTANCY: SAUDI ARABIA http://hdr.undp.org/sites/all/themes/hdr_theme/country-notes/SAU.pdf

9. HUMAN DEVELOPMENT INDEX: SAUDI ARABIA http://hdr.undp.org/sites/all/themes/hdr_theme/country-notes/SAU.pdf

10. WHY INFECTIOUS DISEASE ?  Increasing burden of non-communicable disease worldwide  Infectious disease remains a significant threat overall, particularly among the poor and most vulnerable  Children at the greatest risk  Let’s take a closer look…

11. UNICEF State of the World’s Children Report, 2008

12. PROXIMAL CAUSE CHILD MORTALITY #1: PNEUMONIA – 19%  Meta-analysis of studies that examined risk factors of death among children under 5 with Acute Lower Respiratory Infection (ALRI) in LMICs  Compiled 77 studies from 39 countries Sonego et al., 2015, PLoS ONE http://www.plosone.org/article/fetchObject.action?uri=info:doi/10.1371/journal.pone.0116 380&representation=PDF

13. RISK/PROTECTIVE FACTORS OF DEATH RELATED TO ALRI  severity of pneumonia  age less than 2 months  diagnosis of Pneumocystis Carinii  chronic underlying diseases  HIV/ AIDS  severe malnutrition  young maternal age  low maternal education  low socio-economic status  second-hand smoke exposure  indoor air pollution  Immunization  good antenatal practices Sonego et al., 2015 http://www.plosone.org/article/fetchObject.action?uri=info:doi/10.1371/journal.pone.0116 380&representation=PDF

14. Distal young maternal age low maternal education low socio-economic status severe malnutrition Proximal chronic underlying diseases (e.g. HIV) severity of pneumonia age less than 2 months diagnosis of Pneumocystis Carinii Outcome Death- pneumonia/ ALRI

15. HISTORICAL CASE—JOHN SNOW AND THE CHOLERA EPIDEMIC IN 19 TH CENTURY LONDON  Tested hypothesis – cholera was a waterborne infectious disease  Hypothesized it was a pathogen that affected alimentary canal (mouth as entry point) [theoretical orientation]  Observed cholera epidemic in the London neighborhood in the area of Broad Street [developed hypothesis]  He compared drinking water habits of those affected versus those not affected by cholera-related death [collected empirical data to test hypothesis]  Occurrence of cholera-related death was higher among those exposed to Broad Street pump

16. DISTRIBUTION OF DEATHS FROM CHOLERA IN THE BROAD STREET NEIGHBORHOOD (AUG 19 - SEP 30, 1854) Aschengrau and Seage, 2008 (p.17)

17. AS SOON AS I BECAME ACQUAINTED WITH THE SITUATION AND EXTENT OF THIS IRRUPTION OF CHOLERA, I SUSPECTED SOME CONTAMINATION OF THE WATER OF THE MUCH-FREQUENTED BROAD STREET PUMP, NEAR THE END OF CAMBRIDGE STREET; BUT ON EXAMINING THE WATER, ON THE EVENING OF THE 3 RD OF SEPTEMBER, I FOUND SO LITTLE IMPURITY IN IT OF AN ORGANIC NATURE THAT I HESITATED TO COME TO A CONCLUSION. FURTHER INQUIRY, HOWEVER, SHOWED ME THAT THERE WAS NO OTHER CIRCUMSTANCE OR AGENT COMMON TO THE CHOLERA OCCURRED, AND NOT EXTENDING BEYOND IT, EXCEPT THE WATER OF THE ABOVE MENTIONED PUMP. John Snow, 1855; Aschengrau and Seage, 2008

18. 20 TH CENTURY TRANSITION IN NORTH AMERICA  Increase in sanitation systems  Availability of clean drinking water  Identification of specific microorganisms for infections—link to better treatments  Antibiotics  To date, most effective vaccines were developed in the 20 th century  Improvement in economic conditions/ nutritional status  Advancement of health care services

19. McKeown, Thomas. Determinants of Health

20. EXAMPLES OF PROGRESS VS. PROGRAM CONSTRAINTS/FAILURES  Program successes:  smallpox eradication  reductions in under 5 child mortality (globally)  oral rehydration therapy  access to HIV treatment  Program failures:  urban/ rural differential  persistence in water-borne illnesses resulting from poor water quality and limited access to sanitation facilities

21. Aschengrau and Seage, 2008 DEFINITION OF EPIDEMIOLOGY  The study of the distribution and determinants of disease frequency in human populations, and  The application of this knowledge to control health problems

22. FRAMEWORK FOR CRITICAL EVALUATION OF EPIDEMIOLOGIC STUDIES  What were the objectives/ specific aims of the study?  What was the setting for the study?  What was the study design?  What was the source population for the study?  How were study participants selected?  What was the participation rate of those selected to participate in the study?

23. FRAMEWORK FOR CRITICAL EVALUATION OF EPIDEMIOLOGIC STUDIES (CONT.)  What was the primary exposure of interest? How was it defined?  What was the primary disease of interest? How was the disease status defined?  What variables have been collected to examine confounding or effect modification?  What was the analysis strategy? What were the main results of the study?  What measures of association were used?  What were the conclusions?

24. FRAMEWORK FOR CRITICAL EVALUATION OF EPIDEMIOLOGIC STUDIES (LIMITATIONS)  Was the study design suitable for the objectives of the study?  Was the setting appropriate for the objectives and design of the study?  Were participants enrolled in a manner that would minimize error (i.e. minimize selection bias, enhance generalizability)?  Did the assessment of exposure minimize misclassification and information bias, including recall bias?

25. FRAMEWORK FOR CRITICAL EVALUATION OF EPIDEMIOLOGIC STUDIES (LIMITATIONS)  Did the assessment of disease minimize misclassification and information bias, including recall bias?  If the study was longitudinal, what was the loss to follow-up and how might it affect the results?  Was there any potential for confounding in the study results? If yes, was it appropriately addressed?  Were there any other potential effect modifiers that the authors could have examined?  What was the potential for the role of chance to affect the results?  Did the methods and results correspond with the discussion/conclusions provided by the authors?

26. Adapted from Monson (1990), Aschengrau & Seage (2008) FRAMEWORK FOR CRITICAL EVALUATION OF EPIDEMIOLOGIC STUDIES (LIMITATIONS)  Did the authors adequately describe the limitations of the study in the discussion?  What were limitations in generalizability, if any?  What do you think should be the next steps following the conclusions of the study?

27. WHY DOES THIS MATTER?– HOW DOES THIS CONTENT RELATE TO PUBLIC HEALTH?  When developing policies or designing programs, there is significant value in relying on existing documentation of ‘what works’ vs. ‘what doesn’t work’  It is also good to know/ understand where there is currently limited or controversial evidence available

28. WHY DOES THIS MATTER?– HOW DOES THIS CONTENT RELATE TO PUBLIC HEALTH?  By reviewing existing literature and documentation on a given policy or programmatic approach, one can learn from the successes and mistakes of past efforts, saving ‘new’ initiatives in other settings time and resources  To adequately evaluate existing literature, one needs sufficient training/ background

29. WHY DOES THIS MATTER?– HOW DOES THIS CONTENT RELATE TO PUBLIC HEALTH?  Having the ability to understand elements of a given study and interpret the results, while considering threats to validity or limitations in generalizability is a key building block to making policy and program decisions that are evidence based  The goal of this course, therefore, is to provide the foundation for these building blocks so that you have greater capacity to interpret existing literature and documentation on a given topic

30. Ciliska et al., 2008 EVIDENCE-BASED PUBLIC HEALTH: STAGES

31. Ciliska et al., 2008 EVIDENCE-BASED PUBLIC HEALTH: STAGES

32. CHOLERA IN HAITI – CASE STUDY DISTAL AND PROXIMAL RISK FACTORS FOR TRANSMISSION ( Grandesso F et al. Epidemiol. Infect. (2014), 142, 1625– 1635.) “Two community-based density case-control studies were performed to assess risk factors for cholera transmission during inter-peak periods of the ongoing epidemic in two Haitian urban settings, Gonaives and Carrefour. The strongest associations were: close contact with cholera patients (sharing latrines, visiting cholera patients, helping someone with diarrhea), eating food from street vendors and washing dishes with untreated water. Protective factors were: drinking chlorinated water, receiving prevention messages via television, church or training sessions, and high household socioeconomic level. These findings suggest that, in addition to contaminated water, factors related to direct and indirect inter-human contact play an important role in cholera transmission during inter-peak periods.”