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VIRUSES
 Viruses are not
considered ALIVE
because they are:
– Acellular (not made of
cells)
– No metabolism
– No homeostasis
– No reproduction
outside of host cell
T4 Bacteriophage- virus that
infects bacteria
So what is a virus?
 Viruses are particles
made of only 2 things:
– Protein (makes up a
cover called the
capsid)
– Genetic material
(either DNA or RNA,
but not both)
Human Papillomavirus- causes
WARTS (including genital and
anal warts)
Typical Viruses

T4 Bacteriophage
Influenza virus
A virus infecting a bacterium:
Diseases caused by viruses:
 Warts
 Cervical cancer
 Herpes simplex 1 (cold
sores)
 Herpes simplex 2 (genital
sores)
 Chicken pox
 Shingles
 Mononucleosis
 Roseola
 Ebola
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Polio
Common cold
Rubella
Yellow fever
Encephalitis
Rabies
Measles
Mumps
Influenza
Leukemia
HIV
The only hope you
have if you’ve been
infected with a virus is:
Your own immune
system!
Vaccinations
 Weakened viruses
(attenuated) or pieces of
viruses are introduced
into the body
 Your immune system (B
cells) will make
ANTIBODIESproteins that will attach
to a virus and alert your
immune system to
destroy them
Ebola
 RNA virus
 4 types: Ebola Zaire,
Sudan, Reston and Tai
 Reston only infects
monkeys
 Transmission: close
person to person contact
and body fluids
 Corpses highly infectious
 Zaire strain 90% fatal
 Blood vessels attacked
and destroyed- patient
bleed to death internally
Ebola, continued
 Doctors working
with Ebola
patients wear
“space suits” to
prevent
becoming
infected
African countries with recorded
Ebola outbreaks:
Small Pox
 DNA virus
 Transmitted through droplets
of water while coughing or pus
from blisters
 Once used as a biological
warfare technique during
French and Indian War
 Symptoms appear after 7-14
days
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High fever
Malaise
Back ache
Headache
Followed by rash
Treatment for Small Pox
 Last recorded case of
small pox on Earth
was this man in
Somalia
 Treatments: IV
fluids, fever-reducers,
antibiotics to prevent
secondary bacterial
infection
Vaccination for Small Pox
 Vaccination was
discontinued in US in
1972
 Currently, about 50% of
US population has not
been vaccinated
 Antibodies last in blood
stream for 5 to 15 years
Polio
 Transmitted by water
contaminated with
polio victims’ feces
 Today children
receive 4 vaccinations
between ages 2
months and 4 years
 1979- polio
eradicated from US
Who is this person?
Polio
 total number of cases
reported world-wide
on May 12, 2005:
155
 In the 1950,
summertime was
scary for parents
because many
children became
infected with polio
Symptoms of Polio
-in 95% of cases, there are
NO symptoms
-flu
-diarrhea
-fever
-sore throat
-meningitis
-paralysis
Dr. Jonas Salk:
developed polio
vaccine in 1955
Dr. Albert
Sabin
developed the
ORAL polio
vaccine in 1957
Viruses and Plants
 Viruses can infect
bacteria, fungi and
plants as well as
animals
 This is the Tobacco
Mosaic Virus
Herpes
Genital warts
Herpes
 50-80% of American Population is infected with
Herpes Simplex 1 (cold sores, mouth lesions)
 At least 20% of American population infected
with Herpes Simplex 2 (genital herpes)
 NO CURE!!!!!
 As yet, no vaccine, but it is being studied
 Transmission: skin to skin contact
 Mouth herpes can be transmitted to a person’s
genitals, and vice versa
 Recurrences happen about 4 times per year, and
are triggered by stress, fatigue, diet, skin irritation
Chicken Pox
Measles
Mumps