1. Infectious Diseases
Ch. 13

2. Collaborative Questions
Define Infectious (Communicable) Disease Examples?

3. What are some ways diseases can be spread?
What is a pathogen?
What is a virus?
What are some ways diseases can be spread?
What is happening in the body when an infection is present in a living organism?
What is a vaccines
How do they work?

4. Infectious (Communicable) Diseases
Any disease that is caused by an agent that has invaded the body
Can be passed from one person to another person, from food or water, from animals, or from something in the environment
Examples:
Colds, flu, tuberculosis, MRSA, Ebola

5. All infectious diseases are caused by:
PATHOGENS
Any agent that causes disease
Bacteria, viruses, fungi, protists, parasites

6. Pathogens
Bacteria:
Tiny, single-celled organisms that live almost everywhere on Earth
Most bacteria are harmless and help with bodily functions
Bacteria in mouth, intestines
Harmful bacteria make you sick when they grow on or in your body
Example:
Some give off poisons (tetanus/toxins) that damage cells
Sinus infections
Most harmful bacteria are killed by our immune system, others need antibiotics to treat and cure infections

7. Pathogens Viruses: Smaller than bacteria
Disease-causing particles made up of genetic material surrounded by a coat of protein
the virus finds a living “host cell” and forces it to reproduce and “attack” more cells
Colds, flu, measles, AIDS

8. Pathogens Fungi (fungus) Protists Parasites Rickettsia
Organisms that absorb and use nutrients from other living or dead organisms
Mushrooms
Athlete’s foot, ringworm
Protists
Larger and more complex than bacteria
Malaria
Parasites
Animals—get their energy and nutrients by feeding on other living organisms
Lice, tape worms, etc.
Rickettsia
Pathogens that resemble bacteria
Invade cells of other organisms
Enter humans through bites from fleas, ticks, or lice
typhus

9. How are they transmitted (spread)?
Person to person
Airborne (sneezing, coughing, touching anything drops landed on) kissing, drinking from same glass, direct contact (tetanus)
Dirty Hands Suck
Food and water
Contaminated food (from humans, from infected animal)
Examples?
Water from streams or lakes, sewage,
Typhoid, cholera, dysentery
Environment
Pathogens are all around you—few can cause disease
Tetanus present in soil
Animals
Pathogens live on/in animals
Ringworm from pets, mosquitos carry malaria, yellow fever, encephalitis, ticks carry Lyme disease

10. How to treat… Bacterial diseases Viral Diseases Fungal Infections
Antibiotics-medicines used to kill or slow the growth of bacteria
Penicillin
CANNOT be used to treat colds or viral diseases
Antibiotic resistance: bacteria are no longer killed by a particular antibiotic
Improper use=build up of antibiotic resistant bacteria
Viral Diseases
Not much is known, so most concentrate on relieving symptoms and stopping production of viruses inside cells
Fungal Infections
Over-the-counter or prescription medicine
Protistan, parasitic Infections
Prevention—good hygiene, sanitation

11. Protection Against Diseases read pgs. 638-644
Immune System- general and specific
Network of cells, tissues, organs, and chemicals that fight off pathogens
Physical and Chemical Barriers
First line of defense
Physical—skin (sweat and oil) and mucous membranes (mucus and cilia)block pathogens from entering the body
Chemical—enzymes (stomach acid, tears)

12. Protection Inflammatory Response-2nd line of defense
A reaction to tissue damage caused by injury or infections
Prevents further tissue injury and stops invading pathogens
Immune System- general
Made up of different types of blood cells and proteins called antibodies-(act against a specific pathogen)
Cells move through bloodstream and lymphatic system
A network of vessels that carry a clear fluid called lymph throughout the body—pick up bacteria and viruses and delivers them to the lymph nodes
Collection of WBCs in lymph nodes while fighting infection

13. Protection- specific
Antigen-a substance capable of triggering an immune response
Found on the surface of pathogens and in toxins
Immune System
White Blood Cells
Primary job=defend against disease
Phagocytes (to eat)
A specific white blood cell that attacks invading pathogens
Engulfs pathogens and then destroys them with chemicals (enzymes)
Creates pus
A collection of dead white blood cells and damaged tissue—may collect at the site of inflammation as a response to harmful bacteria
Macrophages-a type of phagocyte that destroys pathogens by making antigens (recognized my WBCs) to trigger an immune response
Result=IMMUNITY
The stat of being protected against a particular disease

14. Protection- specific Lymphocyte
A specialized white blood cell that coordinates and performs many of the functions of specific immunity
T cells, B cells, NK cells
Recognize antigens not made by the body (non-self)
B cells- produce antibodies to neutralize the pathogen
T cells- produce powerful enzymes to kill the infecting pathogen
Helper T cells trigger production of B cells and NK cells
NK Cells- attack and destroy infected cells
**attack only infected cell—NOT pathogen

15. Protection
Vaccines
Substances made of killed or weakened pathogens or from genetic material introduced into the body to create immunity
The body begins to make WBCs called memory cells
If the specific pathogen enters the body , the memory cells and their antibodies fight the pathogen before it can cause disease
May need boosters for vaccines
Flu?

16. Questions With a partner, answer questions #1 and #3 on page 644
Then, write a story with a phagocyte as the main character.
This story should be an imaginative description of a phagocyte joining the inflammatory response to stop invading pathogens after some kind of injury to the body. Your stories can be funny or sad, but all should accurately describe the strategy against disease.

17. TED Talks
A next-gen cure for killer infections

18. Common Infectious Diseases Bacterial
Tetanus
Symptoms- Severe muscle spasms
Transmission- Tetanus causing bacteria found in soil
Prevention- vaccine and boosters
Treatment- antibiotics
Strep Throat
Symptoms- sore throat, fever, yellow or white specks on tonsils
Transmission- contact with mucus from infected person
Prevention- avoid contact
Meningitis-inflammation of membranes covering brain and spinal chord
Symptoms- severe headache, fever, stiff neck, sensitivity to light, nausea
Transmission- contact with saliva or mucus from infected person
Prevention- vaccine, avoid contact
Treatment- antibiotics—if caught early enough

19. Bacterial cont. Sinus Infection
Symptoms- headache, tenderness of sinuses, thick greenish mucus, pressure in head
Transmission- contact with mucus
Prevention- avoid contact and allergens
Treatment- ??
Salmonellosis- an infection of the digestive system
Symptoms- headache, cramps, diarrhea, nausea, vomiting
Transmission- eating contaminated food
Prevention- thorough cooking, hand washing, refrigeration
Treatment- OTC meds for symptoms, sometimes antibiotics

20. Common Infectious Diseases Viral
Flu
Symptoms- headache, sore muscles and throat, fever, vomiting, ect.
Transmission- contact with saliva or mucus
Prevention- vaccine and avoid contact
Treatment- rest, fluids
Cold
Symptoms- sore throat, sneezing, runny nose, mild cough
Prevention- wash hands, avoid contact
Mumps
Symptoms- pain and swelling of glands in throat, fever, headache
Transmission- contact with infected airborne droplets and infected person
Prevention- vaccine
Treatment- see doc. Rest, fluids

21. Viral cont. Measles Mononucleosis Hepatitis
Symptoms- fatigue, runny nose, cough, fever, small white dots in mouth, rash on body
Transmission- contact with saliva or mucus
Prevention- vaccine
Treatment- see doc. Rest, fluids
Mononucleosis
Symptoms- fever, swollen lymph nodes, sore throat, weakness
Prevention- avoid eating/drinking after infected person
Hepatitis
Symptoms- inflammation of liver, jaundice, fever, darkening of urine
Transmission- contact with bodily fluids, contaminated food or water
Prevention- vaccine for A and B, wash hands, avoid contact
Treatment- see doc. Rest, meds, no cure for Hep. B and C

22. You are a scientist for the CDC and have just discovered a recent outbreak of a new disease. As the head scientist, it is now you responsibility to describe this disease, how it is spread, and how to prevent it.
The following must be provided in your document:
Name of disease
Cause of disease
Symptoms of disease
Transmission of disease
Prevention methods
Treatment