Transcript Microbes = Microorganisms

Microorganisms and Human
Disease
Microbiology - Virology
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Microbiology refers to the study of life and
organisms that are too small to be seen with
the naked eye.
Virology –
Study of viruses
Microbes = Microorganisms
Minute living things that individually are too
small to be seen by the naked eye.
They include bacteria, protozoa, fungi and
microscopic algae.
It also includes viruses, those noncellular
entities sometimes regarded as being at the
boarder of life and nonlife.
Microbes can be present on any
surface
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Soil
Air
Food
Solids
Liquids
Bacteria
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Are alive. They can reproduce without a host.
Some are Heterotrophs, they eat organic material
waste.
Single-celled.
Prokaryote – genetic material is not enclosed in a
nucleus. Opposite of Eukarote.
Generally reproduce by dividing into two equal
daughter cells – called binary fission.
Shape – Most commonly are rod-like, spherical,
ovoid and spiral. Uncommon shapes include starshaped and square.
Cocci
Bacilli
Spirilla
Simplest Forms of Life!!!!
Bacteria are very small.
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The average bacterium is about one
micron in length that means you could
line up about 1000 bacteria end to end on
the head of a pin.
If you were to add up the weight of all the
bacteria on the planet, it would come out
to about 20 times the weight of all the
people, animals, and plants on earth!
That’s a lot of bacteria!
A mountain or the tip of a pin?
Oh no we are outnumbered!
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So you may be wondering,
with so many bacteria out
there, why don’t we get sick
more often? That’s because
there are actually very few
kinds of bacteria that make
people sick.
Pathogenic bacteria –
disease producing or cause
bacterial disease
Many bacteria are
beneficial.
Good Bacteria
Archaebacteria – bacteria that make
their homes in extreme environments
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Thermoacidophiles – live in extreme heat
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Methanogens – live in anaerobic (no
oxygen) environments
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Halophiles – live in highly salty
environments
Bacteria Video
Bacteria__A_Review.asf.lnk
What is making me sick?
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Before the discovery of
microbes people
believed the cause of
illness and death was
due to cast spells,
touching toads, and
punishments from God.
The first Observations
In 1665 the first microbes
were viewed with the help of
a crude microscope.
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Between1673-1723, Anton
van Leeuwenhoek wrote
and drew pictures of what he
called “animalcules” that he
scraped from his teeth.
Strep Throat – Where at school can
you catch it?
MRSA – Staphylococcus aureus –
where at school can you catch it?
Lyme Disease – Where at school can
you catch it?
Tetanus – Where at school can you
catch it?
Tooth decay
Streptococcus pneumoniae and
Neisseria meningitidis
Antibiotics: A fortunate accident.
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Are powerful medicines
that fight bacterial
infections
The first antibiotic was
discovered in 1928.
Alexander Fleming was
about to throw out
some culture plates
contaminated by mold
when he noticed that
bacteria had stopped
growing around the
area of mold.
Antibiotic Video
Do you have any questions so far?
Viruses
In 1935, an American chemist,
William M. Stanley, isolated the
tobacco mosaic virus. At about the
same time the invention of the
electron microscope made it possible
to see viruses for the first time.
Viruses
 Are smaller in size than bacteria.
 They are acellular.
 They are simple in structure – a core
with either DNA or RNA
 Have to have a host cell in order to
multiply.
 Antibiotics do not cure viral diseases
 Shape – crystal, cylinder, sphere, spacecraft
Shapes
Viral Disease
 A viral infection is any type of illness
or disease caused by a virus.
 A viral infection occurs when a virus
enters the body through such
processes as breathing air
contaminated with a virus, or insect
bite.
 Vaccines can give one immunity from
viral disease
Virus Video
Introduction_to_Viruses.asf.lnk
Varicella – Chicken Pox
Mumps & Measles
Epstein-Barr Virus:
Mono - “The Kissing Disease”
Human Papillomavirus
“Warts”
Hepatitis C
Immunity Video
Immunity_and_Vaccination.asf.lnk
Any questions about viruses?
Ticks and Fleas and Mosquitoes!
Oh my!
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A vector is an insect or any living carrier
that transmits an infectious agent.
Bubonic Plague
The Black Death, a medieval pandemic that swept
through Asia and Europe. It reached Europe in the late
1340s, killing an estimated 25 million people. The Black
Death lingered on for centuries, particularly in cities.
Parasites – an organism that
derives nutrients from a living host
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Head Lice - causes itching
Tapeworms - causes malnutrition
Malaria – causes death
Giardia – causes diarrhea
Mutagen –
an agent in the environment that
causes mutations in DNA (Deoxyribonucleic acid)
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Caused by chemicals – Fetal Alcohol
Syndrome –
Alcohol (wine, beer, or liquor) is the
leading known preventable cause of
mental and physical birth defects in the
United States.
Caused by radiation – even ultraviolet light
Now that your totally grossed out
do you have questions?
Yikes! Can I Catch It?
Infectious Disease
 A disease that can be
transmitted from:
 Person to person
 Animal to person
 Insect to person
 AIDS
 Colds
 Flu
Noninfectious disease
 A disease that cannot be
shared from one person
to another.
 Asthma
 Cancer
 Epilepsy
Personal conditions that
promote disease.
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Poor hygiene
Weak immune system
A break in skin
Overuse of antibiotics
How do we catch a
disease?
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By inhalation - “catching a cold”
By ingesting
Through any body opening
Through a break in the skin
How does my body defend
itself?
Skin, hair, mucus, tears
Stomach acid
Inflammation, fever, vomiting, diarrhea
Immune system
Epidemic or Pandemic?
Conditions Conducive to
disease
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Poverty
Unsanitary food and water
Overcrowding
Animals
Poor sanitation
What does our future
hold?
 Even though the United States has
continued to grow in population, the rate
of deaths by infectious disease has
decreased.
Do you think the US will continue to
sustain this trajectory? Why or why not?
Last chance for questions!