Download Causes of Diseases

Causes of Diseases
Ms. Edmonson
Objectives
 Identify
characteristics of bacteria, fungi,
viruses, parasites and prions.
Disease Causing Agents
 Bacteria
 Fungi
 Viruses
 Parasites
 Prions
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.
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
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.
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.
Bacteria Diseases
Some diseases caused by bacteria are:
 Anthrax
 Tuberculosis
 Kennel cough
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.
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.

Fungal Disease
Some common fungal diseases are:
 Ringworm
 Yeast infections
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.

Viral Diseases
Some viral diseases are:
 Foot-and-mouth disease
 Parvoviruses
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.
Parasitic Infections
Some parasites that cause infections are:
 Internal
 Flukes
 Roundworms
 External
 Lice
 Mosquitoes
 Flies
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.
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.
Prion Diseases
 Mad
Cow Disease
 bovine
 Scrapie
spongiform encephalopathy
Review
 Identify
characteristics of bacteria, fungi,
viruses, parasites and prions.