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Viruses
Smallpox
The Year Was 1777
• It was a bold executive decision. Faced with a bio-terrorist
threat, the commander in chief issued an order that every
soldier be inoculated against smallpox, despite serious
concerns about the medical risks involved.
• The Commander in Chief of the Continental Army was
George Washington.
• Hearing of possible enemy
plans to infect his troops
with the dreaded smallpox
virus, the future president
had all recruits to his ragtag
army “vaccinated” with
infected material
• This was especially daring
because it was during the
period that the church was
condemning innoculation.
• Washington’s call proved to be right. He subsequently
lost no soldiers in the great smallpox epidemic that
swept the Colonies, and indeed some historians believe
this decision in large part determined the outcome of the
War of Independence.
The distribution
of the smallpox
rash is usually
similar to that
shown here. It is
most dense on the
face, arms and
hands, legs and
feet.
The trunk has
fewer pocks than
the extremities.
Smallpox on Infant
Smallpox
• Believed to have
originated over 3,000
years ago in India or
Egypt
• Considered to be one
of the most
devastating diseases
known to humanity.
• In some ancient cultures, smallpox was such a
major killer of infants that custom forbade the
naming of a newborn until the infant had caught
the disease and proved it would survive.
• Fatal Infectious Disease (severe rash
which leaves scars, fever, headache,
vomiting and diarrhea. )
• No Treatment / No Cure
•Vaccination Available
• Direct Person-to- Person Contact
• Used in Biological Warfare during
French and Indian War
• In 1763 Sir Jeffrey Amhurst, commander in chief of
the British forces fighting a North American Indian
uprising west of the Allegheny mountains, wrote to
Colonel Bouquet: "Could it not be contrived to send
the Smallpox among those disaffected tribes of
Indians?"
• Bouquet replied: "I shall try and inoculate them with
some blankets, and take care not to get the disease
myself.
Smallpox
Cycle
• The rash
appears 2 to 4
days after the
patient first
becomes ill
with fever
Smallpox
Cycle
• On the second
day of rash,
more papules
appear.
Although they
differ somewhat
in size, note that
they all have a
very similar
appearance.
Smallpox
Cycle
• By day 3, the
rash has
become more
distinct and
raised above
the skin
surface. Fluid is
accumulating in
the papules to
form vesicles.
Smallpox
Cycle
• By day 4, the
vesicles are more
distinct. Although
they contain fluid,
they feel very firm
to the touch. When
broken, they do
not collapse
because the fluid is
contained in many
small
compartments.
Smallpox
Cycle
• By day 5, the
fluid in the
vesicles has
become cloudy
and looks like
pus. At this stage,
the pocks are
called pustules.
At this time, the
fever usually rises
and the patient
feels more ill than
before.
Smallpox
Cycle
• On day 7, the rash is
definitely pustular.
Note that the pocks,
although varying
somewhat in size, all
resemble each other
in appearance. The
rash is now so
characteristic that
there should be no
mistake in diagnosis.
Smallpox
Cycle
• During days 8
and 9, the
pustules
increase
somewhat in
size. They are
firm to the
touch and
deeply
embedded in
the skin.
Smallpox
Cycle
• Gradually the
pustules dry up and
dark scabs form.
The scabs begin to
appear between 10
and 14 days after
the rash first
develops. The scabs
contain live
smallpox virus.
Until all scabs have
fallen off, the
patient may infect
others.
Smallpox
Cycle
• By day 20, the scabs have
come off and lightcoloured or depigmented
areas are observed.
The skin seldom returns
to its normal appearance.
Scars which last for life,
often remain (especially
on the face). Such scars
are an indication of
previous infection with
smallpox.
• Smallpox had two main
forms:
– Variola Major
– Variola Minor.
• The two forms showed
similar lesions. The
disease followed a milder
course in variola minor,
which had a case-fatality
rate of less than 1%.
• The fatality rate of variola
major was around 30%.
• There are two
rare forms of
smallpox:
– Hemorrhagic
– Malignant.
• Hemorrhagic is
invariably fatal,
the rash is
accompanied by
hemorrhage into
the mucous
membranes and
the skin.
• Malignant smallpox
is characterized by
lesions that did not
develop to the
pustular stage but
remained soft and
flat.
• It was almost
invariably fatal.
• Smallpox is transmitted from person to
person by infected aerosols and air droplets
spread in face-to-face contact with an
infected person after fever has begun,
especially if symptoms include coughing.
• The disease can also be
transmitted by contaminated
clothes and bedding, though
the risk of infection from this
source is much lower.
• Ro = 5 to 7 from an Index
Case
Ro = Reproductive Ratio
• When
– Ro < 1
• the infection will die out in the long run (provided
infection rates are constant). But if
– Ro > 1
• the infection will be able to spread in a population.
Large values of R0 may indicate the possibility of
a major epidemic.
Values of R0 of well-known
infectious diseases
Desease
Mode of Transmission
Measles
Airborne
Pertussis
Airborne droplet
Diphtheria
Saliva
Smallpox
Social contact
Polio
Fecal-oral route
Rubella
Airborne droplet
Mumps
Airborne droplet
HIV/AIDS
Sexual contact
SARS
Airborne droplet
Influenza (1918 Strain)
Airborne droplet
Ro
12–18
12–17
6–7
5–7
5–7
5–7
4–7
2–5
2–5
2-3
Smallpox
Vaccine
• Edward Jenner's
demonstration, in
1798, that
inoculation with
cowpox could
protect against
smallpox brought
the first hope that
the disease could
be controlled.
• “Pox Type” Virus
• Live Virus Vaccine
• Reactions Vary to
Vaccine
• 15-52 Persons
Experience Severe
Reactions
• 1-2 People will Die
• Bifurcated (TwoPronged) Needle
Accidental autoinoculation of cheek
with vaccine virus,
approximately 5
days old. Primary
take on arm, 10-12
days old.
Accidental auto-inoculation of eyelid with
vaccine virus
West Nile Virus
West Nile virus was first
isolated from a febrile adult
woman in the West Nile
District of Uganda in 1937.
WNV
•
•
•
•
•
•
•
Mosquito-borne Virus
Causes Encephalitis or Meningitis
Bird  Mosquito  Horse or Man
No Treatment
No Human Vaccine
1% Case Fatality Rate
Epidemiologists Use Sentential Surveillance
Transmission Cycle of
West Nile Virus
Horses and Humans are
Accidental Dead End Hosts
Mosquito to Bird
Bird to Mosquito
1999 – 25 Cases
2000 – 60 Cases
2001 – 738 Cases
2002 – 15,257 Cases
2003 – 5,181 Cases
Hantavirus
Hantavirus
• Fatigue, Fever, Muscle Aches
• Lungs Fill with Fluid
• Respiratory Failure
• Cardiac Failure
• 1990’s in Four Corners N.M.
• Virus Shed in Mouse Droppings
• No Treatment, No Cure
• No Vaccine / High Case Fatality
Hemorrhagic Fevers
•
•
•
•
Ebola
Denge
Lassa
Marburg
Ebola
Transmission?
• Researchers do not know exactly how Ebola is
spread. However, they have strong reason to
believe that the first patient becomes infected
through contact with an infected animal.
• The Ebola virus is then spread from human to
human by:
1.
direct contact with the blood and/or
secretions of an infected person.
2.
contact with objects (fomites), such as
needles, that have been contaminated
with infected secretions.
Volunteers in protective clothing
remove the infected bodies and
disinfect the houses to prevent the
spread of Ebola.
Ebola – Level 4 CDC
Outbreak—Ebola
“Odoch Walter [seated], 21,
was vomiting blood. An
ambulance driver is spraying
him before he puts him in the
vehicle. In case he did have
Ebola, they were trying to keep
him and the ambulance ‘clean.’
“To be sprayed like that in the
face, by this person who’s
completely covered in plastic
and rubber and treats you as a
threat to their life—it’s all
pretty horrible. He died two
days later.”
“At Lacor Hospital, the head nurse and Matthew Lukwiya, a doctor,
are looking out at nurses who are grieving coworkers who’ve died.
They’re terrified to go back into the hospital because of the virus.
Lassa Fever
•
•
•
•
•
•
Acute Viral Illness / West Africa / 1969
Endemic in Africa
50% Case Fatality Rate / Deafness
Multimammate Rat is Reservoir
Aerosolized Rodent Urine and Droppings
Fever, Pain in Chest, Back Pain, Cough,
Abdominal Pain, Vomiting, Diarrhea, Facial
Swelling, Bleeding from all Mucosal Membranes
• No Treatment, No Vaccine
Dengue Hemorrhagic Fever
• Mosquito-borne / Aedes Mosquito
• Tropical and Sub-Tropical Regions
• 1950’s Epidemics in Philippines and Thailand
/ Today Asia
• 2/5 of World’s Population at Risk
• 50 Million Cases Yearly
• 50% to 90% Exposed Become Diseased
• Case Fatality Rate 20%
• Flu-Like Disease / Photophobic/
Hemorrhagic Phenomena / Liver
Enlargement Resulting in Circulatory
Failure
• No Treatment / No Cure / No Vaccine
Marburg Fever
• Marburg Virus Disease, and previously also
known as green monkey disease due to its
primate origin. Also found in Fruit Bats in
some areas.
• Marburg originated in Central and East Africa,
and infects both human and nonhuman primates.
• The disease is spread through bodily fluids,
including blood, excrement, saliva, and vomit.
Bioterrorism?
• The two viruses considered to be the
greatest bioterrorism threats are Ebola and
Marburg, the two members of the filovirus
family, which are categorized as category A
bioweapon agents. These viruses
characteristically cause high mortality and
morbidity, are person to person spread, are
highly infectious at a low dose by the
aerosol route, are stable in the environment,
and large-scale production is feasible.
Cold or Influenza
If you have:
Do you have a cold?
Or Influenza?
Fever
Probably not
Likely - Especially if it’s high
Headache
Probably not
Likely
Body Aches
If they are minor
Likely - If they are severe
Fatigue
If it is mild
Likely – Exhaustion
Sneezing
Probably so, if no fever
Possibly, if with fever
Stuffy Nose
Probably so, if no fever
Possibly, if with fever
Sore throat
Probably so, if no fever
Possibly, if with fever
Cough
If it is mild
Possibly - If it is severe
Chickenpox
1. Varicella
2. Very Contagious
3. Shingles Later in Life
4. Infectious From 1 Day
Before Rash till 5 Days
After Rash Appears
5. Body, Throat, Mouth,
Ears
6. Encephalitis / Pneumonia
Chickenpox
Classic case of chickenpox
of the newborn
Chickenpox,
hemorrhagic
Infant with necrotizing fasciitis, a complication of varicella
Secondary Staph Infection in Chickpox lesions
Confused with Smallpox?
Shingles
• Shingles (sometimes called herpes zoster) is a
painful, blistering skin rash due to the varicellazoster virus, the virus that causes chickenpox.
• After you get chickenpox, the virus remains
inactive (becomes dormant) in certain nerves in
the body. Shingles occurs after the virus
becomes active again in these nerves years
later.
• Risk Increases If:
1. You are older than 60
2. You had chickenpox before age 1
3. Your immune system is weakened by
medications or disease
Roseola
• 6 Months to 2 Years
• 1 Week Duration
• High Fever
• Irritability
• Sore Throat / Runny Nose
• Swollen Lymph Nodes
• Can Trigger Febrile
Seizures
• Encephalitis
Other
Symptoms
• bulging of the
fontanel, or soft
spot, in the head of
an infant
• cough
• mild diarrhea
• mild sore throat
• puffy eyelids
• runny nose
Rubeola (Measles)
• Measles is a highly
contagious - but rare respiratory infection
that's caused by a virus.
It causes a total-body
skin rash and flu-like
symptoms, including a
fever, cough, and runny
nose.
• May see Koplik’s Spots
in Mouth
Koplik’s Spots small,
white spots (often on a
reddened background)
that occur on the inside
of the cheeks early in the
course of measles.
Rubella /
German
Measles / 3 Day
Measels
• Rubella — commonly known as German measles
or 3-day measles — is an infection that primarily
affects the skin and lymph nodes.
• It is usually transmitted by droplets from the nose
or throat that others breathe in.
• It can also pass through a pregnant woman's
bloodstream to infect her unborn child.
• A generally mild disease in children, the primary
medical danger of rubella is the infection of
pregnant women, which may cause congenital
rubella syndrome in developing babies.
Maternal Infection
• In the first 12 weeks of pregnancy results in
birth defects in up to 85 percent of cases
• From 13 to 16 weeks of gestation results in
birth defects in 54 percent of cases
• At the end of the second trimester results in
birth defects in 25 percent of cases
Complications
• Miscarriage
• Stillbirth
•
•
•
•
Blindness
Deafness
Heart Abnormalities
Mental Retardation
Polio
Polio
•
•
•
•
Virus Shed in Feces
1950’s Closed Swimming Pools
95% Unapparent Infections
4% to 8% Minor Illness / Respiratory Infections
with Complete Recovery
• 1% to 2% Result in Aseptic Meningitis with
Stiff Neck, Back and Legs Involved with
Complete Recovery
• <2% Result in Permanent Partial Paralysis or
Death
Iron Lungs
• The iron lung was the first
effective treatment for
patients paralyzed by polio
that couldn't breathe.
• The first model consisted of a
tank and a pair of vacuum
cleaner blowers.
• Because patients lived inside
the respirators for weeks,
months or even years at a
time, later models had
portholes through which
clinicians could give care.
• The respirator shown here
was used in the early 1930s.
Los Angeles Polio Ward with Iron Lungs in Use 1952
Two children with
polio receiving
physical therapy
The Salk vaccine, was developed
by Dr. Jonas Salk in 1952.
Kurt Achenbach, 7, a first-grader in 1954, bucks up his courage for his
polio immunizatoin. Kurt was one of 1.8 million “polio pioneers” who
volunteered to test the Salk vaccine.
Aerial view of
a crowd
awaiting polio
immunization,
San Antonio,
1962
Did You Know?
• When the first, injectable polio vaccine was
tested on some 1.8 million children in the
United States in 1954, within 9 days there
was huge epidemic of paralytic polio in the
vaccinated and some of their parents and
other contacts. The US Surgeon General
discontinued the trial for 2 weeks.
Oral vaccine prevents the
vaccinee from acting as a
carrier of wild type
poliovirus, and as stated,
confers long-lasting
immunity. The OPV is also
easily administered by
giving children a sugar cube
or sugar liquid containing
the vaccine, neither of
which requires extensive
medical training to be
administered.
This 1963 poster
featured CDC’s
national symbol of
public health, the
"Wellbee",
encouraging the
public to receive an
oral polio vaccine.
Chronic Fatigue Syndrome
• As immunization with the Salk vaccine got underway the
polio epidemics came to a halt, and in 1979, the disease
was declared eradicated in the U.S. But the polio story
isn't over. Some 70 percent of survivors now suffer from
postpolio syndrome, or weakness in previously
unaffected muscles.
Hot Spots Still Exist
• Today about
the only
polio we see
in the United
States is in
children
adopted
from other
countries.
Herpes
• Herpes is a general term for two different
diseases: one that affects the area around the
mouth (oral herpes, also known as cold
sores) and another that affects the area
around the genitals (genital herpes).
Herpes
• Two Kinds
1. HSV Type 1
- Fever Blisters and Cold Sore
- Genital Herpes
- 50% to 80% Americans Carry Antibodies
2. HSV Type II
- Usual Cause of Genital Herpes
Congenital Herpes
• Herpes cannot be cured.
• Once either virus is inside the body and
settles itself into the nerve cells, it cannot be
eliminated. However, herpes sores can be
treated.
• Treatment can speed up healing time,
reduce pain, and delay or prevent additional
flare-ups. Typically, treatment is used only
during a flare-up.
HIV / AIDS
"One of the most
recognized AIDS
posters every
produced"
USA, 1987
2007
1970-1980
• We do not know how many people developed
AIDS in the 1970s, or indeed in the years before.
Neither do we know, and we probably never will
know, where the AIDS virus HIV originated. But
what we do know is:
• "The dominant feature of this first period was
silence, for the human immunodeficiency virus
(HIV) was unknown and transmission was not
accompanied by signs or symptoms salient
enough to be noticed.
1981
• Kaposi's Sarcoma (KS) was a rare form of relatively benign
cancer that tended to occur in older people.
• At about the same time there was an increase, in both California
and New York, in the number of cases of a rare lung infection
Pneumocystis carinii pneumonia (PCP)3.
• "A doctor was treating a gay man in his 20s who had
pneumonia. Two weeks later, he called to ask for a refill of a
rare drug that I handled. This was unusual-nobody ever asked
for a refill. Patients usually were cured in one 10-day treatment
or they died"
1982
• We definitely had a new disease that was linked to it's
initial occurrence in gay men, with the Lancet calling it
the 'gay compromise syndrome', whilst at least one
newspaper referred to it as GRID (gay-related immune
deficiency) and another as “gay cancer.”
• In June a report of a group of cases amongst gay men
in Southern California, suggested that the disease might
be caused by an infectious agent that was sexually
transmitted.
August 1982
• By August the disease was being referred to by it's new
name of AIDS24. The word AIDS was an abbreviation of
Acquired Immune Deficiency Syndrome.
• " When it began turning up in children and transfusion
recipients, that was a turning point in terms of public
perception. Up until then it was entirely a gay epidemic,
and it was easy for the average person to say 'So what?'
Now everyone could relate.“
Harold Jaffe of the CDC for newsweek -34
1983
• Evidence emerged that men could pass the
disease on via heterosexual transmission to
women.
• The sense of urgency was greatest for
haemophiliacs
• In May 1983, doctors at the Institute Pasteur in
France reported that they had isolated a new
virus, which they believed was the cause of
AIDS.
HIV Ward in Thailand
AIDS claims so many lives that orphanages are set up for the
children of the victims. Picture from Ethiopia.
Early Posters / Informative
Then Posters Moved to Getting
the Point Across in a Few Words
Today
Forget Being Politically Correct
Let’s Just Save Lives
"During the early
years of the epidemic,
there was a great deal
of fear over the
transmission of HIV.
This even extended to
sharing the chalice
during communion in
church. The Terrence
Higgins Trust
produced this poster to
try and quell any fears
that people had."
UK, 1986
HIV / AIDS
• Acquired immune deficiency syndrome or
acquired immunodeficiency syndrome (AIDS
or Aids) is a collection of symptoms and
infections resulting from the specific damage to
the immune system caused by the human
immunodeficiency virus (HIV) in hu.mans
• The late stage of the condition leaves individuals
susceptible to opportunistic infections and
tumors.
• Although treatments for
AIDS and HIV exist to
decelerate the virus
progression, there is
currently no known cure.
• HIV, et al., are
transmitted through
direct contact of a
mucous membrane
or the bloodstream
with a bodily fluid
containing HIV,
such as blood,
semen, vaginal
fluid, preseminal
fluid, and breast
milk.
HIV / AIDS
• UNAIDS estimates that 36.9 million people
were living with HIV/AIDS worldwide as of the
end of 2007.
• Since the epidemic began, an estimated 21.8
million people have died of AIDS
• 100% Case Fatality Rate
• >75% of all individuals with AIDS are male.
• Acquired Immune Deficiency Syndrome
• Incubation Period of 5-10 Years
• Increase in TB, Pneumonia, Persistent Severe
Diarrhea, Skin Infections, Cancer, etc.
• 13-20 Million People Infected with HIV
• No Vaccine, No Cure, Drug Therapy Does
Exist
• STD / Needles / Body Fluid Exchange