Epidemiology Lecture Notes

Overview

• Lecturer: Elena
• Content Warning: Discussion includes COVID-19, relevance to healthcare workers and others affected.

Historical Perspective: The Black Death

• Time Period: 14th Century (1347-1351)
• Location: Started in Eastern Asia, spread through the Silk Road to Europe.
• Impact: Killed over 50 million people, about one-third of Medieval Europe's population.
• Cause: Yersinia pestis bacterium, leading to bubonic plague.
• Transmission: Flea bites from infected animals (e.g., rats, rabbits).

Cultural Impact

• Works by famous writers and philosophers, e.g., Vocatio's Decameron.
• Art motifs like Le Dance Macabre and the concept of the Plague Hag.

Types of Plague

1. Septicemic: Infects the blood, most severe, rare.
2. Pneumonic: Infects the lungs, spread through droplets.
3. Bubonic: Swellings (buboes) in lymph nodes, filled with pus.

Understanding Epidemiology

• Definition: Study of the spread, control, and prevention of diseases.

Key Terms

• Morbidity Rate: Number of cases divided by the at-risk population.
• Mortality Rate: Population that dies from the disease.
• Incidence Rate: Number of new cases in a specific time period.
• Prevalence: Total number of existing cases.
• Endemic: Constantly present in a particular area.
• Epidemic vs. Pandemic: Unusually large number of cases (epidemic) vs. worldwide spread of epidemics (pandemic).

Historical and Recent Pandemics

• Examples include SARS, MERS, 2009 Swine Flu, and COVID-19.
• Not the first pandemic in 100 years contrary to popular belief.

Plague Doctors

• 17th-century concept during the Great Plague of London.
• Protective gear included a beaked mask with herbs, waxed leather coat, and a long stick.

Disease Reservoirs

• Human, non-human animals, and environmental sources.
• Identifying reservoirs helps in disease prevention and control.

Control and Prevention Methods

• Improved sanitation, controlling reservoirs and vectors, vaccinations, and antibiotics.

Eradication of Smallpox

• Smallpox is the only disease eradicated globally.

Guinea Worm Eradication

• Parasitic infection spread through drinking contaminated water.
• Carter Center's efforts since 1986 resulted in a significant decrease in cases.

Modern Challenges

• The rise of new diseases (e.g., HIV, SARS, COVID-19).
• Re-emergence of diseases due to vaccination declines (e.g., whooping cough, measles, mumps).

Lab and Final Notes

• CDC epidemiology mission game.
• Typhoid Mary: Case study of an asymptomatic carrier.
• Final exam: Closed-note, covering material since the midterm.
• Reminder: Cover cough, wash hands, wear masks.

Reflection

• Encouragement of continued education and attention to infectious diseases and their societal impact.