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Communicable Disease
Virus- united streaming video clip 54 min
Communicable disease or Infectious disease is an illness
caused by a pathogen that can be spread from one living thing
to another
Pathogen – a germ that cause disease
Virus – smallest known pathogen –
takes over a cell & tries to make
more
Cold, mumps, chicken pox,
HIV, influenza
Bacteria – single cell organism
- most are beneficial (around 1000)
- around 100 can cause disease
syphilis
gonorrhea
strep throat
tetanus
Toxin – a substance that is poisonous
Fungi – single cell or multi-cell parasitic organism
Live on skin, mucus membrane, & lungs
Athlete’s foot, ringworm, jock itch, nail infections
ringworm
Athlete’s foot
Protozoa – single-cell organism that produce toxins
Malaria, African sleeping sickness,
Helminth – parasitic worm from undercooked pork, fish, or
from poor hygiene –affects your digestive system
Tapeworms, pinworms,
hookworms
How pathogens are spread:
1. Direct contact: shaking
hands, kissing, sexual
intercourse, body fluids
exchange or contact,
2. Air born – sneezing or
coughing,
3. Contaminated objects – combs,
toothbrushes, razors, eating utensils, etc.
4. Contaminated food or water
5. Contaminated animals
Immune System – removes harmful organisms from the blood
and combats pathogens
Composed of body organs, tissue, cells, and chemicals
*Skin – 1st line of defense -
*Perspiration and oils kill pathogens
*Tears help prevent things from entering the eyes
*Mucus & hairs that line the nose help trap & destroy
pathogens
*Saliva helps kill off some pathogens
*Stomach Acid helps kill some pathogens
Resident bacteria- It lives in the skin, in the mouth and
intestines to help protect from harmful bacteria
Host – the plant or animal on which the parasite feeds
Lymphocytes – are white blood cells that help the body fight
off pathogens
Two types:
B cells – produce antibodies – special protein
that fight infection
T helper cells – signal for the b- cells
Macrophage – a white blood cell that surrounds and destroys
pathogens
Once a pathogen is destroyed, it is taken to the Spleen
Phagocytosis - . Process that the white blood cells surround
and eat up invading bacteria
Immunity – the body’s resistance to disease-causing agents
Active immunity – presence of antibodies
Passive immunity – introducing antibodies into a person’s
body
Vaccine or Immunization – substance containing a dead or
weaken pathogen that is introduced into the body
- given by injection or orally
- diphtheria, pertussis ( whooping cough), tetanus (every
10 years), measles, mumps, rubella (German Measles),
polio, Hepatitis A & B, & chicken pox