Technological Advances and Limitations after 1900 | AP World History: Modern

Overview

• The 20th and 21st centuries witnessed significant medical innovations and the effects of globalization on disease management.
• Scientific advancements improved life expectancy and addressed deadly pathogens, yet new epidemics emerged due to global travel and urbanization.
• Modern disease management reflects the intersection of technological progress, social inequality, and ecological vulnerability.

Pandemics and Epidemics in the Modern Era

The 1918 Influenza Pandemic

• Occurred during the final year of World War I.
• Rapid spread through military bases and urban centers.
• Approximately 50 million fatalities globally; 195,000 Americans died in October 1918.
• Led to early public health efforts:
  • Hand-washing campaigns
  • Mask mandates
  • School and public space closures

COVID-19 (SARS-CoV-2)

• Emerged in late 2019, becoming a global pandemic by 2020.

• Prompted rapid vaccine development:

  • mRNA vaccines (e.g., Pfizer, Moderna)
  • Adenovirus-based vaccines (e.g., AstraZeneca, Johnson & Johnson)

• Demonstrated globalization's strengths (information sharing, cooperation) and risks (viral transmission).

• Impact of Pandemics:

  • Medical breakthroughs
  • New public health policies
  • Changes in social behavior

Contagious vs. Chronic Diseases

Contagious Diseases

• Spread through direct contact, air, water, or vectors (e.g., flu, malaria, COVID-19).

Chronic Diseases

• Long-term conditions related to aging or lifestyle (e.g., cancer, heart disease, diabetes).

Global Patterns

• More Developed Countries (MDCs): Chronic diseases dominate due to longer life expectancy.
• Less Developed Countries (LDCs): Infectious diseases are more prevalent due to healthcare access limitations.

The HIV/AIDS Crisis

Origins and Spread

• Emerged in late 20th century; initially termed GRID in the U.S.
• Caused by HIV, compromising the immune system.
• Transmission through unprotected sex, blood transfusions, shared needles.

Medical Developments

• Antiretroviral therapy (ART) transformed HIV from fatal to manageable.
• PrEP (Pre-Exposure Prophylaxis) introduced in the 2010s to prevent transmission.

Global Challenges

• Sub-Saharan Africa remains heavily affected.
• Limited access to contraception and healthcare.
• NGOs focus on education, condom distribution, culturally appropriate outreach.

Other Major Diseases Since 1900

• Malaria (Mosquito-borne, affects LDCs in Sub-Saharan Africa and South Asia, treated with antiparasitic drugs).
• Tuberculosis (TB) (Airborne, affects LDCs in Africa and Southeast Asia, treated with antibiotics).
• Cholera (Waterborne, affects LDCs in South Asia, Africa, Caribbean, treated with rehydration and antibiotics).

Diseases of Aging and Behavior

Aging Populations

• Alzheimer's Disease: Affects memory and cognition in seniors.
• Parkinson's Disease: Affects movement, often in aging populations.

Lifestyle Diseases

• Rise in lifestyle-related diseases due to increased food access and reduced manual labor.

• Heart disease, diabetes, and obesity are prevalent in high-income countries and spreading to middle-income nations.

• Described as "diseases of affluence," linked to caloric surplus, sedentary lifestyles, processed diets.

Key Terms

• Adenovirus, Alzheimer's Disease, Cancer, Cholera, Chronic Diseases, Common Cold, Contagious Diseases, Coronavirus, COVID-19, Dementia, Diabetes, Flu, H1N1 flu, Heart Disease, Malaria, Meningitis, mRNA vaccines, Parkinson's Disease, Polio, Pre-existing Conditions, SARS-COV-2, Spanish Flu, Sub-Saharan Africa, Truvada, Tuberculosis (TB), Zambia, Kenya, and Uganda.