1. Causes of Diseases Ms. Edmonson

2. Objectives  Identify characteristics of bacteria, fungi, viruses, parasites and prions.

3. Disease Causing Agents  Bacteria  Fungi  Viruses  Parasites  Prions

4. Bacteria  Bacteria consist of only a single cell.  Bacteria are among the earliest forms of life  Bacteria have been found that can live in temperatures above the boiling point and in cold that would freeze your blood.  Bacteria fall into a category of life called the Prokaryotes.

5. Bacteria  There are thousands of species of bacteria, but all of them are basically one of three different shapes.  rod- or stick-shaped  little ball shaped  helical or spiral shaped

6. Bacteria  Bacteria live on or in just about every material and environment on Earth.  Each square centimeter of your skin averages about 100,000 bacteria.  Some bacteria are photosynthetic.  Other bacteria absorb food from the material they live on or in.

7. Bacteria  Some bacteria move about their environment by means of long, whip-like structures called flagella.  Other bacteria secrete a slime layer and ooze over surfaces like slugs.

8. Bacteria Diseases Some diseases caused by bacteria are:  Anthrax  Tuberculosis  Kennel cough

9. Fungi  Fungi causes a number of plant and animal diseases.  Fungi are more chemically and genetically similar to animals than other organisms, making fungal diseases very difficult to treat.

10. Fungi  Fungi are eukaryotic.  Fungi include single-celled creatures that exist individually and multicellular bunches.  Fungi live in the soil and on your body, in your house and on plants and animals, in freshwater and seawater.  They can spread either by forming reproductive spores that are carried on wind and rain.

11. Fungal Disease Some common fungal diseases are:  Ringworm  Yeast infections

12. Viruses  A virus is basically a tiny bundle of genetic material.  Viruses are found on or in just about every material and environment on Earth from soil to water to air.  Viruses exist for one purpose only to reproduce. To do that, they have to take over the reproductive machinery of suitable host cells.

13. Viral Diseases Some viral diseases are:  Foot-and-mouth disease  Parvoviruses

14. Parasites  Diseases caused by parasites are widespread in domestic animals and wildlife.  Parasites may be internal or external.  External parasites live or feed on the surface of the animal's body.

15. Parasitic Infections Some parasites that cause infections are:  Internal  Flukes  Roundworms  External  Lice  Mosquitoes  Flies

16. Prions  Newly identified protein particles called prions have been found in the brains of animals.  They are thought to be misshapen or abnormal versions of proteins normally found in animals or people.

17. Prions  Very little is known about prions.  Scientists suggest that they spread when a prion comes into contact with the normal version of the protein and causes the normal protein to change shape and become a prion, too.

18. Prion Diseases  Mad Cow Disease  bovine spongiform encephalopathy  Scrapie

19. Review  Identify characteristics of bacteria, fungi, viruses, parasites and prions.