Unit 3: The HIV Epidemic

Group Discussion:

  1. What makes a disease an epidemic?

The rapid spread of a disease that affects a broad community.

  1. What factors might influence the spread of a disease?

How closely people live, population density, how the disease has spread, vaccines, shared food/water source

What is an epidemic?

  • An infectious disease that spreads beyond a local population or geographical area

    • Ease of transmission (i.e., coughing spores compared to having to have physical contact)

    • Human behavior (i.e., hygiene, sexual practices)

    • Public health (i.e., vaccines, clinics)

    • Travel and trade

    • Living conditions (i.e, type of housing, availability of clean water, amount of space available, mold in space)

    • Warfare (i.e, increased infections due to lack of access to medicine and medical care)

    • Weather and climate change (i.e, natural disasters—hurricanes or tornadoes—can cause standing water)

What causes disease?

  • Microscopic organisms and particles

    • Bacteria: single-cell, prokaryotic

      • Normal flora of the body—live on/in us, but have benefits

      • Pathogenic bacteria can cause disease

    • Viruses: not cells, not alive

    • Protozoa: single-cell, eukaryotes (motile)

      • Ex. Malaria

    • Multicellular parasites

      • Ex. worms

    • Fungi: eukaryotic

      • Ex. single-cell—yeast infection, multicellular—mushrooms

    • Prions: infectious proteins

Where do microbes come from?

  • Our environment

  • Animals and insects (vectors)

  • Human hosts

How does the disease get in?

  • Despite its protective features, disease can still enter our body:

    • Inhaled (airbone)

    • Ingested (food poisoning, Mad cow disease)

    • Wounds (bite, scratch, abrasion, needles or sharps)

    • Sexual contact (kissing, vagina, oral, sex)

    • Blood exchange (bloodborne—needle sticks)

    • Breastfeeding (HIV)

Common Infections:

Bacteriaal:

  • Conjunctivitis, aka “pink eye.”

  • Food poisoning

  • Meningitis

  • Pnneumonia

  • STDs

  • Bronchitis

  • Urinary tract infections

  • Ear infections

  • Strep throat

  • Pertussis (“whooping cough”)

  • Stomach ulcers

  • Toxic shock

Viral:

  • Conuctivitis

  • Stomach flu (gastroenteritis)

  • Meningitis

  • Pneuomia

  • STDs

  • Flu: influenza, H1N1 (swine), H5N1 (avian)

  • Colds

  • COVID-19

  • Chickenpox

  • Cold sores

  • Mononucleosis (“mono”)

  • Warts

Which infectious disease has killed the most people worldwide?

  • Tuberculosis

    • An estimated 1 billion deaths: 4,300 deaths/day

    • TB has influenced cultures worldwide

      • Building of towns

      • Social behavior (romanticism, stigma)

    • TB is a disease of injustice

      • We have the medicine to cure TB

      • The cure is unaffordable in poor countries

Other Infections

  • Yeast infections (vaginal, jock itch, athlete’s foot, ringworm)

  • Head or pubic lice

  • Giardiasis or amebiasis (diarrhea)

  • Tomoplasmosis

  • Ascaris or pinworms

  • Scabies (mites)

  • Disease borne by other organisms (vectors)

  • Malaria

  • Lyme disease

  • Creutzfeld-Jakob disease and other prion diseases

STDs and STIs

  • Mechanism of spread

    • Vaginal, anal, and oral intercourse

    • Contaminated body fluids or skin surfaces

  • Treatments:

    • Bacterial: can be treated with antibiotics

      • Chlamydia, gonorhea, syphillis, vagintitis

    • Fungal: can be treated with anti-fungal agents

    • Viral: some vaccines are available, limited antiviral drugs

      • HPV (human papilloma virus), herpes, hepatitis A and B, HIV

    • Other pests: hygine, medicated shampoos, various drugs