chapter 19-3: diseases caused by bacteria and viruses bacteria and viruses are everywhere in nature,...
TRANSCRIPT
![Page 1: Chapter 19-3: Diseases Caused by Bacteria and Viruses Bacteria and viruses are everywhere in nature, but only a few cause disease. Disease-causing agents](https://reader036.vdocument.in/reader036/viewer/2022081418/56649e3a5503460f94b2c736/html5/thumbnails/1.jpg)
Chapter 19-3: Diseases Caused by Bacteria and Viruses
• Bacteria and viruses are everywhere in nature, but only a few cause disease.
• Disease-causing agents are called pathogens.
![Page 2: Chapter 19-3: Diseases Caused by Bacteria and Viruses Bacteria and viruses are everywhere in nature, but only a few cause disease. Disease-causing agents](https://reader036.vdocument.in/reader036/viewer/2022081418/56649e3a5503460f94b2c736/html5/thumbnails/2.jpg)
Bacterial Disease in Humans• Many bacteria live
on and within our bodies.
• Growth of pathogenic bacteria disrupts the body’s equilibrium by interfering with its normal activities and producing disease.
![Page 3: Chapter 19-3: Diseases Caused by Bacteria and Viruses Bacteria and viruses are everywhere in nature, but only a few cause disease. Disease-causing agents](https://reader036.vdocument.in/reader036/viewer/2022081418/56649e3a5503460f94b2c736/html5/thumbnails/3.jpg)
How do bacteria cause disease?
1. They damage the cells and tissues of the infected organism directly by breaking down the cells for food.
2. Or they release toxins (poisons) that travel throughout the body interfering with the normal activity of the host.
![Page 4: Chapter 19-3: Diseases Caused by Bacteria and Viruses Bacteria and viruses are everywhere in nature, but only a few cause disease. Disease-causing agents](https://reader036.vdocument.in/reader036/viewer/2022081418/56649e3a5503460f94b2c736/html5/thumbnails/4.jpg)
Preventing Bacterial Disease
• Many bacterial diseases can be prevented by vaccines (a preparation of weakened or killed pathogens).
• When injected into the body, a vaccine may prompt the body’s immunity to the disease.
![Page 5: Chapter 19-3: Diseases Caused by Bacteria and Viruses Bacteria and viruses are everywhere in nature, but only a few cause disease. Disease-causing agents](https://reader036.vdocument.in/reader036/viewer/2022081418/56649e3a5503460f94b2c736/html5/thumbnails/5.jpg)
Treating Bacterial Disease• If infection occurs, drugs can
be used to destroy bacteria. • These drugs include
antibiotics, which are compounds that block the growth and reproduction of bacteria.
• A reason for increased human life expectancy is an increased understanding of how to prevent and cure bacterial infections.
![Page 6: Chapter 19-3: Diseases Caused by Bacteria and Viruses Bacteria and viruses are everywhere in nature, but only a few cause disease. Disease-causing agents](https://reader036.vdocument.in/reader036/viewer/2022081418/56649e3a5503460f94b2c736/html5/thumbnails/6.jpg)
Viral Disease in Humans• Viruses produce disease by disrupting the
body's normal equilibrium.• How do viruses cause disease?
1. Lytic: viruses can attack and destroy certain cells in the body, causing symptoms of the disease.
2. Lysogenic: other viruses cause infected cells to change patterns of growth and development.
![Page 7: Chapter 19-3: Diseases Caused by Bacteria and Viruses Bacteria and viruses are everywhere in nature, but only a few cause disease. Disease-causing agents](https://reader036.vdocument.in/reader036/viewer/2022081418/56649e3a5503460f94b2c736/html5/thumbnails/7.jpg)
Viral Disease Prevention/Treatment
• Vaccines are the best protection against viral diseases, but only work if used before an infection begins.
• Viral diseases cannot be treated with antibiotics.
• Symptoms may be treated with over-the-counter medicines.
![Page 8: Chapter 19-3: Diseases Caused by Bacteria and Viruses Bacteria and viruses are everywhere in nature, but only a few cause disease. Disease-causing agents](https://reader036.vdocument.in/reader036/viewer/2022081418/56649e3a5503460f94b2c736/html5/thumbnails/8.jpg)
Bacterial Diseases Viral Diseases
• Lyme disease
• Tetanus
• Tuberculosis
• Bacterial meningitis
• Strep throat
• Common cold
• Influenza
• AIDS
• Chicken pox
• Hepatitis B
• West Nile
![Page 9: Chapter 19-3: Diseases Caused by Bacteria and Viruses Bacteria and viruses are everywhere in nature, but only a few cause disease. Disease-causing agents](https://reader036.vdocument.in/reader036/viewer/2022081418/56649e3a5503460f94b2c736/html5/thumbnails/9.jpg)
40-1: Infectious Disease
• Disease: any change, other than an injury, that disrupts the normal function of the bodyo Can be inherited, caused
by materials in the environment, or produced by pathogens (disease causing agents).
![Page 10: Chapter 19-3: Diseases Caused by Bacteria and Viruses Bacteria and viruses are everywhere in nature, but only a few cause disease. Disease-causing agents](https://reader036.vdocument.in/reader036/viewer/2022081418/56649e3a5503460f94b2c736/html5/thumbnails/10.jpg)
The Germ Theory of Disease• Idea that infectious
diseases are caused by microorganisms, or germs
• Observed by French chemist Louis Pasteur and German bacteriologist Robert Koch
![Page 11: Chapter 19-3: Diseases Caused by Bacteria and Viruses Bacteria and viruses are everywhere in nature, but only a few cause disease. Disease-causing agents](https://reader036.vdocument.in/reader036/viewer/2022081418/56649e3a5503460f94b2c736/html5/thumbnails/11.jpg)
Koch’s Postulates• Series of guidelines used
to identify the microorganism that causes a specific disease
• These rules are important because identifying pathogens that cause disease is the first step toward prevention or cures.
![Page 12: Chapter 19-3: Diseases Caused by Bacteria and Viruses Bacteria and viruses are everywhere in nature, but only a few cause disease. Disease-causing agents](https://reader036.vdocument.in/reader036/viewer/2022081418/56649e3a5503460f94b2c736/html5/thumbnails/12.jpg)
The Postulates (or rules)1. The pathogen should always be found in a
sick organism, not a healthy one.2. It must be isolated and grown in the lab.3. When injected in a new host, it should cause
the same original disease.4. The injected pathogen should be isolated
from the new host and identical to the original pathogen.
![Page 13: Chapter 19-3: Diseases Caused by Bacteria and Viruses Bacteria and viruses are everywhere in nature, but only a few cause disease. Disease-causing agents](https://reader036.vdocument.in/reader036/viewer/2022081418/56649e3a5503460f94b2c736/html5/thumbnails/13.jpg)
Agents of Disease• For many pathogens, the human body
provides just the right conditions for growth.
Agent Example
Viruses Common cold, flu, warts
Bacteria Botulism, Anthrax
Protists Malaria, African Sleeping Sickness
Worms Schistosoma
Fungi Athletes foot, ringworm
![Page 14: Chapter 19-3: Diseases Caused by Bacteria and Viruses Bacteria and viruses are everywhere in nature, but only a few cause disease. Disease-causing agents](https://reader036.vdocument.in/reader036/viewer/2022081418/56649e3a5503460f94b2c736/html5/thumbnails/14.jpg)
Fungi: athlete's foot
Worms:
SchistosomaProtists:
Trypanosoma
![Page 15: Chapter 19-3: Diseases Caused by Bacteria and Viruses Bacteria and viruses are everywhere in nature, but only a few cause disease. Disease-causing agents](https://reader036.vdocument.in/reader036/viewer/2022081418/56649e3a5503460f94b2c736/html5/thumbnails/15.jpg)
How Diseases Are Spread
• Coughing, sneezing, or physical contact
• Contaminated food or water
• Vectors: infected animals that carry pathogens from person to person
![Page 16: Chapter 19-3: Diseases Caused by Bacteria and Viruses Bacteria and viruses are everywhere in nature, but only a few cause disease. Disease-causing agents](https://reader036.vdocument.in/reader036/viewer/2022081418/56649e3a5503460f94b2c736/html5/thumbnails/16.jpg)
Fighting Infectious Diseases• Antibiotics: compound that blocks the growth
and reproduction of bacteria (no effect on viruses)
• Over-the-Counter Drugs: treat only the symptoms, but do not actually treat the cause of the infection