Section 14 vid 3

Biological Hazards

• Biological hazards refer to natural substances that impact human health and well-being.

  • Examples include bacteria, viruses, insects, plants, birds, animals, and humans.

Diseases

Transmissible vs. Non-Transmissible Diseases

• The lesson distinguishes between transmissible and non-transmissible diseases:

  • Transmissible Diseases:

    • Spread from person to person via living organisms (parasites, protozoa, viruses, bacteria).

    • Vectors include insects, bodily fluids, water, food, and air.

  • Non-Transmissible Diseases:

    • Not spread between individuals nor caused by living organisms.

    • Often result from multiple factors and develop slowly.

    • Examples: asthma, cancer, malnutrition, emphysema, diabetes, cardiovascular disorders.

Antibiotic Resistance

• While antibiotics have reduced bacterial diseases, misuse has led to antibiotic resistance:

  • Resistant bacteria can survive antibiotic treatment and reproduce, resulting in a rapid increase in resistant strains.

  • Plasmids (pieces of DNA) can be transferred between bacteria, allowing non-resistant strains to gain resistance quickly.

  • Contributing factors include:

    • Overuse of antibiotics in healthcare and agriculture.

    • Patient misunderstandings and misuse of prescribed antibiotics.

    • According to studies, 50% of prescribed antibiotics may be unnecessary.

    • CDC reports 2 million annual U.S. infections from antibiotic-resistant bacteria, with 23,000 deaths.

    • Resistance rates are significant:

      • 65% for ciprofloxacin

      • Up to 51% for penicillin

    • Some countries report 82% resistance to commonly used antibiotics.

Viral Diseases

• Major viral diseases include flu, Ebola, West Nile virus, and HIV/AIDS:

  • Once viral infections occur, they are often harder to treat than bacterial infections.

  • Vaccines are critical for prevention; examples include smallpox, polio, rabies, measles, and hepatitis B.

  • The WHO identifies 19 diseases with epidemic potential.

Epidemics vs. Pandemics

• Epidemic: localized outbreaks.

• Pandemic: broader, often devastating spread affecting multiple populations.

Factors Increasing Disease Risks

• Several factors increase the risk of infectious outbreaks:

  1. Urbanization and Population Growth:

  • Increases sanitation stress and proximity to animals.

  2. Advances in Farming:

  • Encroaches on wild areas, escalating disease transmission (e.g. Lassa fever from rats).

  3. Climate Change:

  • Increases waterborne pathogens and allows disease vectors to spread further.

  4. International Travel:

  • Facilitates rapid spread of diseases (e.g. SARS outbreak linked to a doctor traveling).

  5. Civil Unrest:

  • Unstable regions struggle with containment during outbreaks (e.g. Ebola in West Africa).

  6. Weak Health Systems:

  • Many developing countries lack adequate healthcare support, leading to rapid disease spread.

  7. Rapid Spread of Information:

  • Misinformation can cause panic and impede effective response.

Examples of Animal-Origin Diseases

• Key diseases include HIV/AIDS, SARS, Ebola, Swine Flu, Rabies, and Avian Influenza:

  • Top lethal diseases linked to animal origins (Ebola, Marburg, Rabies, HIV, Smallpox).

Historical Context

• The 1997 viral outbreak in East Africa serves as an example of how unforeseen circumstances can escalate health crises:

  • El Niño led to increased human-animal interaction and mosquito breeding, causing significant fatalities.

Epidemiological Transition

• As countries industrialize, they transition from infections in childhood to chronic diseases in adulthood:

  • 43% of deaths in developing countries due to infections, compared to 1% in developed countries.

Reflection Questions

• Contemplate personal contributions to antibiotic resistance.

• Consider actions to mitigate this issue in daily life.

• Explore antibiotic resistance in a national or global context and its relation to the tragedy of the commons.