General Ecology, ECOL 3500, University of Georgia

Lecture: Disease

Updated: 16 February, 2009


Topics

  • Don't confuse cause versus effect
    • Agent (cause)
      • Plasmodium parasite
      • HIV
      • Smoking
      • Heavy drinking
      • Lack of exercise; too much (fast) food
      • Lack of seatbelt use
    • Disease (effect)
      • Malaria -- 'bad air' -- Symptoms: fever, malaise, ... possible death
      • AIDS
      • Lung cancer, emphysema
      • Cirrhosis of liver
      • Obesity; Diabetes
      • Windshield shards in head

  • Don't confuse rate versus standing crop
    • Prevalence of disease (standing crop)
    • Incidence of disease (rate of new cases with disease symptoms)
    • Prevalence of infection (propostion of population with infection, not necessarily with disease)
    • Incidence of infection (rate of transmission)

  • Types of disease
    • Infectious
    • Environmental (air pollution, smoking, chemical food poisoning)
    • Genetic -- Developmental
    • Malnutrition
    • Congenital
    • Interaction of above causes

  • Infectious disease transmission
    • Density dependent (airborne, waterborne diseases/agents)
    • Vectored (mosquitoes, ticks, fleas, needles)
    • Close contact (STD's, kissing, scabies)

  • Time lags
    • Short -- diseases of past -- smallpox, measles, polio, TB, ...
      (Caveats: Evolution of drug resistance; Bio-weapons)
    • Long -- diseases of future -- Alzheimer's, Parkinson disease, Chron's disease, many cancers

  • Symptomatic versus asymptomatic
    • Carriers -- Typhoid Mary
    • Site of infection -- Gonorrhea

  • Course of infection -- SIR models: Susceptible -> Infected -> Recovered
    • Susceptible
    • Exposed
    • Infectious (or not)
    • Diseased (or not)
    • Recovered (or not)
    • Immune to future infection (or not)

  • Other considerations
    • Endemic, epidemic, pandemic
    • Emerging diseases, zoonotic and other sources:
      AIDS, Legionnaires disease, Toxic Shock Syndrome, Hanta Virus, Lyme Disease, Purple fever in Brazil
    • Drug resistance
    • Introductions, invasions
    • Climate change
    • Evolution of virulence -- prudent versus pathogenic parasites

  • Emerging technologies
    • Diagnostic testing
    • Genomics: personal genome, risk assessment
    • Internet: reporting, diagnosis, teaching, mapping, ...
    • Database integration and mining
      (Caveat: Ethics of big sister versus big brother; health insurance, employment, ...)
    • Medical automation

  • Larry Brilliant: TED Prize wish: Help stop the next pandemic

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