Disease and Immunity

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Disease and Immunity
Herpes
Polio
Measles
TB
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Pathogens

• Any foreign invader that enters the body and
  causes disease
• Pathogens include
• Bacteria
• Viruses
• protists
• A disease that can spread to others is called
• Infectious
• Contagious
• communicable

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The Bodys Reactions

• The first defense is our skin and mucous
  membranes
• Sweat and oil is toxic to some bacteria
• Mucus will trap invaders
• Fever an elevated body temperature will
  suppress bacterial growth and speed up our immune
  response
• Normal 98.6 degree F / 37 degrees C

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The Bodys Reactions to a localized (small)
infection

• Inflammatory response
• Injured cells release chemical alarm signals
• Capillaries respond by swelling and leaking fluid
  and white blood cells
• Swelled area is warm
• White blood cells arrive to attack
• Pus in wounds is dead pathogens

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Bacteria

• Can be pathogenic

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Characteristics of Bacteria

• How they eat
• Heterotrophic
• Eat other things
• Autotrophic
• Make their own food like plants
• Oxygen requirements
• Anaerobic
• Undergo fermentation (no oxygen)
• Aerobic
• Use oxygen

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Bacteria Classification

• Two Kingdoms
• Eubacteria most common bacterial forms
• All pathogenic bacteria
• Archaebacteria Most primitive bacterial forms
  that live in extreme environments

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Kingdom Eubacteria

• Most common
• 3 basic shapes
• Rod
• Sphere
• Spiral
• Prefix strep Chains
• Prefix staphlo Clusters

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Gram staining

• Bacteria can also be classified by whether or not
  they retain color when stained by a certain
  chemical.
• Whether or not they retain the color is based on
  the components of their outer membrane
• Gram-positive bacteria retain the color (violet)
• Gram-negative bacteria do not retain the color
  and are dyed with a secondary dye which turns
  them pink.

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• Different types of antibiotics are needed to
  treat infections based on whether the bacteria is
  Gram-negative or Gram-positive
• Some antibiotics kill bacteria by damaging their
  peptidoglycan cell wall
• Which bacteria would be resistant to an
  antibiotic that worked in this fashion?

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Bacterial diseases

• Tetanus
• Bubonic plague (The Black Death)
• Bacterial pneumonia
• Sinus infection
• Strep throat
• Tuberculosis (TB)

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Antibiotics and Bacteria

• Antibiotics only work against bacteria!
• Some antibiotics are made from chemicals that
  bacteria and fungi produce naturally
• Penicillin is made is from a type of fungus
• Other antibiotics have been created in medical
  laboratories
• Amoxicillin, Zithromax, Tetracycline, Vancomycin

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Antibiotic Resistant Bacteria

• Remember evolution
• 1) Bacteria have different characteristics due to
  mutations.
• 2) Some of these mutations help the bacteria to
  survive an attack by antibiotics.
• 3) The stronger (more resistant) bacteria survive
  and infect a new person (host).

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Tuberculosis

• Certain types of this pathogenic bacteria can no
  longer be treated by antibiotics
• How can you help to
• stop the spread of
• antibiotic resistant
• bacteria?

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Useful Bacteria

1. Breakdown organic matter and recycle carbon and
   nitrogen
2. Help with the production of food
3. Clean up environmental disasters

Intestinal Bacteria
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Protists

• Single or multicelled organisms that live in
  water
• Plant like or
• animal like

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Three representative protists
flagella
eyespot
Pseudopod false foot

• Euglena

paramecium
amoeba
cilia
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Protist (protozoan) disease

• Malaria
• Anopheles mosquito
• plasmodium
• African Sleeping sickness
• Tsetse fly
• Trypanosoma

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African Sleeping Sickness
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VirusesA paothgen that is unable to grow or
reproduce outside of a host cell. It is
considered non-living
The Common Cold

• Virology is the study of viruses

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Virus Structure
Capsid/

• Viruses are extremely small
• They have a
• Nucleic acid (DNA or RNA)
• Capsid - A protein coat that protects the virus
• Protein tail -used to infect host

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Structure of Influenza Virus
Used to attach to host cell
Glycoprotein
RNA
Capsid
Protein
Protein
Envelope
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Family Virus Disease
Adenovirus Common cold Common cold
Flavivirus Hepatitis C (non-A, non-B)Yellow fever HepatitisHepatitis, hemorrhage
Hepadnavirus Hepatitis B virus (HBV) Hepatitis, liver carcinoma
Herpesvirus Epstein-Barr virus (EBV)Herpes simplex type 1Herpes simplex type 2Human herpesvirus 8 (HHV8) Mononucleosis, nasopharyngeal carcinomaCold soresGenital lesionsChicken pox, shingles
Papovavirus Human papillomavirus (HPV) Warts, cervical carcinoma
Paramyxovirus MeaslesMumpsParainfluenza MeaslesMumpsCommon cold, ear infections
Poxvirus Orthopoxvirus Smallpox (eradicated)
Retrovirus Human immunodeficiency virus (HIV)Human T-cell leukemia virus (HTLV-I) Acquired immunodeficiency syndrome (AIDS)Adult T-cell leukemia, lymphoma, neurologic disease
Rhabdovirus Rabies Rabies
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Viruses and Their Hosts

• When a virus meets a host cell, it can insert its
  genetic material into its host, taking over the
  host's functions
• The infected cell stops producing its own
  proteins and starts to make new viruses!
• Basically, it hijacks the cell!

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Viral Phases

• Lysogenic phase - viruses are dormant inside host
  cells for long periods.
• The host is not sick.
• Lytic phase - The virus is stimulated
• new viruses are formed, self-assemble, and burst
  out of the host cell, killing the cell and going
  on to infect other cells.
• The host is now sick with a viral infection

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Viral Mutations

• Viruses are able to rapidly mutate
• Flu
• HIV
• Attacks white blood cells the cells that
  protect our bodies from germs and infections
• HIV is latent until another infection triggers
  the lytic stage
• Kills white blood cells
• HIV has a high rate of replication and mutation
  which has made it difficult to make a vaccine

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Two Ways to Control Viruses

• Vaccination An injection of a harmless version
  of a virus which causes an immune response.
• The body begins to produces antibodies against
  that virus
• Antiviral Drugs Drugs that slow down or stop a
  viral infection
• Tamiflu

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Acquired Immunity An immunity that develops
after exposure

• 2 kinds
• Active Immunity When your body makes its own
  antibodies
• Getting sick
• vaccines
• Passive Immunity
• Antibodies are given to the person
• Mothers milk

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White Blood Cells (WBC)

• These are your immune cells
• Most are made in your bone marrow
• There are many types
• Lymphocytes
• Leucocytes
• Neutrophils
• B cells, T cells

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WBC that you need to know

• T cells
• Killer cells
• Made in bone marrow
• Attacks a specific pathogen

• B cells
• Made in bone marrow
• Attack a specific pathogen by making antibodies
• They stick to the surface of a pathogen and so it
  cannot infect any other cells

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Memory Cells

• T cells and B cells that remain in the body after
  an infection has been destroyed.
• They provide the body with active immunity in the
  future against that disease
• Your body made memory cells against chicken pox
  when you had it as a kid. You now have life long
  immunity to chicken pox!
• Why cant we get life long immunity to the flu or
  a cold?