Transcript Infections Ppt

Infectious Disease
Bacteria: Friend or Enemy?
WHAT IS AN INFECTIOUS
DISEASE?
Pathogens:
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Bacteria, viruses, parasites, and fungi, called
pathogens are capable of causing a change
that disrupts the homeostasis in the body.
Any disease caused by the presence of
pathogens in the body is called an infectious
disease. The main sources of pathogens are
soil, contaminated water, and infected
animals, including other people
Good Bacteria:
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Not all microorganisms are pathogenic; your
body is host to billions of microorganisms,
most of which are bacteria. These
microorganisms have a symbiotic relationship
with your body helping to keep harmful
bacteria and other microorganisms from
growing.
Good Bacteria:
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If beneficial organisms are eliminated from
your body, pathogens can establish
themselves and cause infectious disease. In
addition, if beneficial organisms enter areas
of the body where they are not normally
found, these formerly harmless organisms
can become potential pathogens
Common Diseases caused by
Pathogens:
Disease
Cause
Affected Organ
Transmission
Smallpox
Virus
Skin
Droplet
Influenza
Virus
Respiratory system
Direct contact
HIV/AIDS
Virus
Immune system
Body Fluid
Hepatitis B
Virus
Liver
Body Fluid
Tetanus
Bacteria
Nervous system
Puncture Wound
Strep Throat
Bacteria
Respiratory system
Droplet
Tuberculosis
Bacteria
Respiratory
Droplet
Strep Throat:
RESERVOIRS OF PATHOGENS
Carriers:
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Main source of human disease pathogens is
the human body.
People may or may not display symptoms of
the illness.
Animals are the other main reservoir for
pathogens, making the eradication of certain
pathogens almost impossible.
TRANSMISSION OF DISEASE
Transmission
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Pathogens can be transmitted to a host from a
reservoir four main ways;
By direct contact; exchange of body fluid
By an object; people handle contaminate objects
then touch face, nose, eyes, etc…
Through the air; person coughs or sneezes
spreading droplets which are then inhaled
By a vector; insects such as mosquitos, ticks
spread pathogens between hosts or reservoirs
Bats are carriers of rabies, an infectious disease:
Mosquitoes carry many infectious diseases:
Viruses:
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Shape: multisided
Structure: contains DNA or RNA, no
cytoplasm or organelles,
Composed of cells: no
Treatments: none, only preventions (antiviral,
vaccines)
Not considered to be alive, must have a host
cell; but destroys the cell
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Examples of diseases: flu, common cold (can
mutate into different forms), viral meningitis,
HIV-AIDS, polio, chicken pox
Flu virus
Bacteria:
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Shapes: spheres, rods, spirals
Structure: single celled with a cell wall and
and organelles but no nuclei
Composed of cells: yes
Treatments: antibiotics, Preventionsantibacterial, bacterial vaccines,
antimicrobials
Found everywhere, can survive without a
host, multiply rapidly and form colonies
(100,000 = size of dime), can be helpful
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Examples of diseases: tetanus, anthrax,
rabies, Lyme disease, bacterial meningitis
E Coli
Lyme Disease
Fungi:
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Shape: numerous
Structure: multi-cellular wit a cell wall and
organelles including a nucleus, but no
chloroplasts
Composed of cells: yes
Treatments: antifungals, antimicrobials
Cannot make their own food, grown on and
feed off of organic matter; some kinds are
beneficial, but others are harmful
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Examples of diseases: athlete’s foot,
ringworm, yeast infections
Athlete’s Foot
Ringworm
Parasites:
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A parasite is an organism that lives on or in a
host and gets its food from or at the expense
of its host.
Parasites can cause disease in humans.
Some parasitic diseases are easily treated
and some are not.
Major types-protozoa, helminths or worms,
and arthropods.
Treatment:
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antibiotics
prevention: drugs that can be taken as a
barrier to certain parasites. improving
sanitary conditions of water and food
sources, proper cooking techniques,
education about personal hygiene, and
control of intermediate and vector host
organisms.
Protozoa
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Single-celled organisms
More than 45,000 species of protozoa are
known, many of which are parasitic.
Cause of more suffering and death than any
other category of disease causing organisms.
dysentary
Helminths:
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Wormlike organisms including nematodes
(roundworms), cestodes (tapeworms), and
trematodes (flukes). Leeches and
heartworms are also helminths.
tapeworm
Arthropods:
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Organisms characterized by exterior
skeletons and segmented bodies. Examples
include the crustaceans, insects, and
arachnids.
Serve as carriers of bacterial and viral
diseases, as intermediate hosts for protozoan
and helminth parasites, and as parasites
themselves.
Mosquitoes, flies, fleas, ticks, mites