4-2

• Disease

  A disorder of structure or function, especially one that produces specific symptoms or that affects a specific location and is not simply a direct result of physical injury
• Evolution of disease

  • Fossil record
  • As humans evolved, so did diseases
  • Ancestors less exposed until settled agriculturally-based communities arose around 10,000 years ago
  • Animals a major part of revolution
  • Close contact in overcrowded unsanitary conditions - animal diseases (zoonotic) jump species
• Major infectious diseases

  • Smallpox
  • Influenza
  • Tuberculosis
  • Malaria
  • Plagues
  • Measles
  • Cholera
• Early beliefs about disease


  • Diseases due to evil spirits, wrath of gods
  • Ancient Egyptians - blocked channels within body – need to be balanced
• Plagues

  • Galen – 'quickly-spreading fatal disease'
  • Lived through Antonine Plague in Roman empire (165-180 AD) - smallpox or measles
  • 2000 deaths/day
  • 5 million total
  • 'Cito, Longe, Tarde' - Hippocrates, Galen 'Leave quickly, go far away, and come back slowly'
• Early theories of disease

  • Miasma theory ('bad air')
  • Humouralism – blood letting balancing of humours
  • Antisepsis - wine vinegar used by Romans
  • Honey to treat wounds
  • Tears of the poppy (laudanum, opium)
• The Black Death


  • 1340s
  • Most deadly pandemic in recorded history
  • Erupted out of central Asia
  • Yersinia pestis spread by fleas on rats
  • Bubonic, pneumonic, septicaemic forms
  • Killed 75-200 million
  • Europe lost 1/3 of its people, China ½
  • Medical faculty of Paris - conjunction of three planets in 1345 caused a "great pestilence in the air"
  • Fear, panic, complete breakdown of society
  • As Europe recovered and entered Renaissance, ancient texts rediscovered, newer texts from Islamic world accessible; older texts questioned
• New empires and epidemics

  • Age of Exploration (15th-17th C)
  • Armies, colonisers, traders imported/exported disease
  • Britain a growing trading nation - thousands succumbed to smallpox, sweating sickness (?hantavirus), bubonic plague epidemics in 16th & 17th C – but developed immunity
  • Old supernatural beliefs survived – Charles II to cure 'king's evil'
• Conquest and colonialism


  • Empire-building
  • 1518: smallpox in South America decimated local population
  • Exposure to new medical knowledge - smallpox inoculation (pustule material injected into skin) successfully imported from China, India, Turkey to Britain, America in early 1700s
  • Columbian exchange
• Theories of disease


  Girolamo Fracastoro (1478-1553) – contagion theory substances on clothing of diseased people 'seeds of disease' entered by breath, blood stream 'germs' capable of self-replication transmitted from one person to another
• Prevention of Infection


  • Advent of microscopes & development of cell theory
  • Louis Pasteur (1822-1895) develops germ theory microorganisms enter body, cause disease vaccination, microbial fermentation, pasteurization
  • proved spontaneous generation false
  • Joseph Lister (1827-1912) surgeon pioneer of antiseptic surgery carbolic acid, aseptic technique
• John Snow 1813-1858


  • Did not accept miasma theory of cholera transmission
  • Published 'On the Mode of Communication of Cholera' in 1849 – entered through mouth
  • 1854 – plotted cases of cholera on map of Soho
  • Able to identify water pump in Broad Street as source of disease
  • Handle of pump removed - cases of cholera immediately began to diminish
  • Germ theory of disease not widely accepted until 1860s
• Koch's postulates 1884


  • Heinrich Robert Koch (1843-1910)
  • German physician
  • Four criteria to establish causative relationship between microbe and disease
  • Cholera, TB; extended to other diseases
  • Germ theory - every human disease caused by microbe or germ, specific for that disease, which can be isolated
• Public health reforms and laboratory research 19th C

  • Industrialised overcrowded 19th C cities havens for diseases typhoid, tuberculosis, cholera
  • Ironically, proponents of miasma theory greatly influenced public health reforms
  • Pasteur, Koch and pupils significantly advanced understanding of disease
  • Resulting Germ theory gradually supplanted prevailing Miasma and Contagion theories
• 20th C revolution in healthcare


  • Despite improvements, infant mortality rates in Britain in 1900 higher than in 1800
  • Poor, ill-nourished children - diphtheria, measles, whooping cough
  • Growing state intervention, biomedical research reversed trend
  • Germ theory - research on newly identified disease pathogens
  • New vaccines, 'magic bullet' antibacterial drugs revolutionised treatment
  • Pinnacle - production of penicillin during Second World War (1939-45)
• Antibiotics


  • 1928 – Alexander Fleming observed bacterial zone of clearing around mould of Penicllium notatum
  • 10 years later further developed by Howard Florey, Ernst Chain (Nobel prize 1945)
  • Department at Oxford penicillin factory
  • Trials at Radcliffe Infirmary Oxford 1941
  • Many other antibiotics developed
  • Modern era - development of antibiotic resistance
• Modern epidemics


  • Spanish Flu pandemic 1918 - At least 50 million people died
  • Infectious diseases continued to decline in developed world, although some smaller epidemics – polio
  • Modern epidemics – AIDS, Ebola
• Causes of death
• Using smallpox as an example, describe how inoculation and vaccination have led to the eradication of a human-only disease


  1. Smallpox in the Ancient and New World - Long relationship with disease unique to humans killed millions

  2. Variola major/minor spread through contact with living sufferers, dead bodies

  3. Especially harsh on previously unexposed populations - 1/3 of Aztecs died following Spanish invasion

  4. Smallpox scars on mummified features of pharaoh Ramses V

  5. Smallpox and the Elizabethans - From 1500s onwards disease reached most parts of world

  6. Survivors carried legacies of smallpox for life – blindness, scars – 'pock-marked'

  7. Shaped beauty patches to camouflage damage

  8. Coated faces with white lead powder

  9. Combating the smallpox epidemic - Scarred survivors gained lifelong immunity

  10. Inducing immunity first exploited in China

  11. Inoculation from as early as 10th C AD

  12. Provoke mild form of disease in healthy people by variolation e.g. blowing powdered smallpox scabs up nose or putting infected needle into muscle

  13. Preventing disease - Local knowledge - itinerant practitioners, word of mouth

  14. Early 1700s - smallpox inoculation (variolation) in parts of Africa, India, Ottoman Empire

  15. 1717 Lady Mary Wortley Montagu saw local women giving inoculations at 'smallpox parties' in Istanbul

  16. On returning to Britain, children inoculated during outbreak 1721

  17. Mixed results

  18. USA - Cotton Mather (churchman) told about inoculation by Onesimus - enslaved Sudanese worker - received treatment as a child

  19. Boston 1721 epidemic

  20. Mather and Zabdiel Boylston (doctor) campaigned for inoculation – much hostility

  21. Ideas spread eventually

  22. Vaccination - Smallpox killed 10% of population in UK

  23. Edward Jenner 1749-1823 - English country doctor, keen inoculator, developed safer, more effective vaccination

  24. Milkmaids caught cowpox (Variolae vaccinae) gained immunity from more dangerous smallpox

  25. 1796 successfully induced immunity using cowpox pustules in local boy, James Phipps

  26. "Saved more lives than the work of any other human"

  27. The slow decline of smallpox - 1853 Smallpox vaccination compulsory

  28. Many other vaccines developed

  29. Global Smallpox Eradication Programme achieved aim in 1979

  30. Bangladesh 1973