AFRL Stragegic NST Plan and FY06 POM Initiative

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Bugs, Drugs, and Thugs Case Studies in Virology
SAFMLS WORKSHOP 12 FEB 2008 DAVID G. WATSON,
MAJ, USAF, BSC
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 1

A 9-year-old black female, a recent émigré from
Haiti, came to a Florida Emergency Room because
of a fever, headache, sore throat and mild cough.
Her parents say that she has been sick for 2-3
days. You note that she has a runny nose and a
mild conjunctivitis. Her temperature is 39,
pulse rate 110 beats/min, blood pressure 90/60 mm
Hg, and respiratory rate 42/min. You note that
her pharynx is very red and that she also has
some bright red spots with white centers on her
buccal mucosa. Her chest is clear. You take a
throat swab and send the child home instructing
the parents to return with the child tomorrow
when you will have the results of the throat
culture.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 1

Question 1 The throat swab is most commonly used
to diagnose?  A) whooping coughB) influenza C)
strep throatD) measles E) diphtheria
Answer C) strep throat This is the most common
use. The swab is streaked on blood agar. If beta
hemolytic colonies are seen the bacteria are
Group A or pathogenic Streptococci.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 1

Question 2 On the whole, would you agree with the
decision to send this child home with no
treatment or instructions for care?  A) Yes,
because even if she had a strep throat, tomorrow
is soon enough to start treatment and viral
diseases can't be cured.B) No, because she may
not come back and miss treatment for a disease
that could result in rheumatic fever.C) No,
because she had a highly communicable disease
that you should have recognized.D) Both B and C
have some merit. Answer D) Both B and C have
some merit.Both the fact that she might not come
back if she starts to feel better and the fact
that she might have a communicable disease should
weigh in your answer.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 1

There are no beta hemolytic colonies seen on the
blood agar plate the next day. The child does
return and when you examine her again you notice
a rash behind her ears and on her face. Careful
examination of the rash shows that it is
maculopapular. Question 3 The absence of beta
hemolytic colonies on the blood agar plate
means?  A) the child does not have scarlet
feverB) the child does not have rheumatic
feverC) the child does not have Rocky Mt.
Spotted feverD) the child has measlesE) the
child has German measles Answer A) the child
does not have scarlet feverScarlet fever is
caused by Group A beta hemolytic streptococci --
it can be thought of as a strep throat with a
rash. This child would have beta hemolytic
colonies on blood agar from the throat swab if
she had scarlet fever.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 1

Question 4 The differential diagnosis for a child
with a rash is quite large. Measles, German
measles and Rocky Mt. spotted fever should be
considered. What are some other agents that can
cause a rash?  A) B19, HHV3, BordetellaB)
chlamydia, Coxsackievirus, EEEVC) hantavirus,
flu virus, HHV3D) Treponema pallidum, B19,
Coxsackievirus Answer D) Treponema pallidum,
B19, CoxsackievirusThese should all be included.
T. pallidum causes syphilis and secondary
syphilis presents with a rash. A good
differential diagnosis for this child's disease
would be measles, German measles, Rocky Mt.
spotted fever, fifth disease, Coxsackievirus
infection, secondary syphilis. You know its not
scarlet fever because of the throat culture. A
few parasitic diseases, that a recent emigrant
could have, also have rashes.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 1

Question 5 You ask the parents if they have seen
any ticks on the child or if she had been
anywhere that she could have been bitten by a
tick. This would bear on the diagnosis of which
of the following?  A) measlesB) secondary
syphilisC) fifth diseaseD) Rocky Mt. spotted
feverE) Coxsackievirus infection Answer D)
Rocky Mt. spotted feverThis rickettsial disease
is spread by ticks.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 1

Question 6 What in the world causes fifth
disease? A) an adenovirusB) a parvovirusC) a
poxvirusD) a herpesvirusE) a picornavirus Answ
er B) a parvovirusIts called B19. B19 is a
virus that commonly infects humans about 50 of
all adults have been infected sometime during
childhood or adolescence. Parvovirus B19
infects only humans.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 1

Question 7 B19 usually causes a very mild
disease. Two groups of people for whom it can be
serious, however, are? A) teenagers and pregnant
womenB) pregnant women and sickle-cell
anemicsC) the sexually promiscuous and drug
addicts D) alcoholics and asplenicsE) smokers
and alcoholics Answer B) pregnant women and
sickle-cell anemics Primary infection in pregnant
women is very serious and can result in death of
the fetus. In patients with sickle-cell
disease, the virus can initiate a transient
aplastic crisis.
Typical giant proerythroblast seen in
B19-associated pure red cell aplasia with highly
uncondensed chromatin and pale purple
intranuclear inclusions (bone marrow aspirate,
hematoxylin-eosin, x1000).
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 1

Question 8 What should have alerted you to the
possibility of measles? A) the conjunctivitisB)
the Koplik spotsC) the runny nose (coryza)D)
the coughE) all of the above Answer E) all of
the aboveThe combination of the three C's
(cough, coryza, conjunctivitis) and Koplik spots
should have been a red flag.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 1

Question 9 Why is it so important to diagnose
measles? A) it can be curedB) the complications
can be preventedC) the child needs to be
vaccinated against measlesD) pregnant women
exposed to the child need to have abortionsE)
all unvaccinated contacts need to be
protected Answer E) all unvaccinated contacts
need to be protectedMeasles is a very serious
and highly communicable disease and all
unvaccinated contacts need to receive the
vaccine. If contacts are less than 1 yr. old or
immunocompromised, hyperimmune serum globulin is
recommended.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 1

Question 10 How is measles normally prevented?
A) DPT vaccineB) MMR vaccineC) killed viral
vaccineD) live oral vaccineE) measles vaccine
is no longer needed Answer B) MMR vaccineThis
is measles, mumps and rubella all are live
attenuated viruses.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 1

Question 11 When is the MMR vaccine usually
given? A) 2, 4, 6, 15 months and 4-6 years.B)
2, 4, 15 months and 4-6 years.C) 2, 4, 6, 15
months.D) 15 months and 4-6 years. Answer D)
15 months and 4-6 years. If you had attended my
SAFMLS workshop last year on Vaccines, you would
have known this!
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 1

Question 12 Why is the MMR vaccine given so much
later than the other childhood vaccines? A) the
live viruses are dangerous until the children
have some natural immunity.B) the vaccines don't
work due to maternal antibody before this
time.C) the immune system is not mature enough
to make antibodies before this time.D) cellular
immunity that is needed will not develop before
this time. E) the vaccines can cause severe
complications in children under 1 yr.
old. Answer B) the vaccines don't work due
to maternal antibody before this time. The
maternal antibody neutralizes the vaccine virus.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 1

Question 13 What is/are the complication(s) of
measles? A) SSPE (subacute sclerosing
panencephalitis) B) viral pneumoniaC) bacterial
pneumoniaD) encephalitis E) all of the
above Answer E) all of the aboveThey can all
occur and all be very serious!
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 1

Question 14 How can measles be confirmed? A)
heterophile antibodiesB) anti-measles IgGC)
anti-measles IgMD) growth of the virus in tissue
cultureE) all of the above Answer C)
anti-measles IgMYou could also look for
measles virus antigen using fluorescent
antibodies to the virus.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 1

A measles antigen detection assay tested positive
for the measles virus. You send the child home
but tell the parents to keep her isolated. Eight
other children and four adults in the same house
were given measles vaccine. One baby was given
hyperimmune serum globulin. Twenty neighborhood
children that had never been immunized were also
immunized. Question 15 How is it that so many
of this child's contacts were not previously
vaccinated? A) the vaccine is only available in
the USA and all the others were immigrants.B)
the vaccine is expensive and only purchased by
those who can afford it.C) the lowest
socioeconomic classes have the poorest
vaccination rates.D) the perceived high
incidence of reactions to the vaccine make it
very unpopular. Answer C) the lowest
socioeconomic classes have the poorest
vaccination ratesThey often "fall through the
cracks," as it were. They either have not been
taught that vaccinations are important, they
don't know where to go to get them, or they don't
have the money, time, or energy to do it.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 1

The sick child appeared to be recovering but
after 10 days had a resurgence of fever, severe
headaches, and seizures. Question 16 This new
development?  A) is normal in the course of
measlesB) signals measles pneumoniaC) occurs in
about 0.1 of measles casesD) is most likely
unrelated to the measlesE) is SSPE Answer C)
occurs in about 0.1 of measles casesMeasles
encephalitis occurs in 1 out of every 1000 or
2000 cases.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 1

Outcome The child was hospitalized and given
supportive care. Although many children suffer
neurological deficits after measles encephalitis,
this child recovered and was left with no
sequelae. She grew up and, fondly remembering
the kindness of the doctors who cared for her,
went to Medical School at the University of
Florida.
Dr. Ertha Pascal-Trouillot later returned to her
native country and, in 1991, became the first,
and only, woman president of Haiti.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 2

A 69-year-old male citizen of Mexico who arrived
a month ago to visit his son and daughter-in-law
in Florida for the summer, was evaluated at an
urgent-care center for a 3-day history of
increasing pain in his left jaw, chest and
shoulder. He also complained of sore throat,
anxiety, insomnia, nausea and vomiting. He said
he had received a spider bite on his left jaw and
that the pain had started after that. His
daughter-in-law commented that he had been
somewhat confused since arriving in Florida and
that she couldn't remember a spider bite. He
was transferred to the hospital and treated for
chest pain, but evaluation ruled out cardiac
disease and pneumonia. He rejected all oral
fluids and continued to complain of the spider
bite. He was sent to the mental health unit
where he was noted to be anxious and have
impaired memory. He was diagnosed with anxiety
disorder and given tranquilizers and discharged.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 2

Question 1 Insects and other arthropods (ticks)
are known to transmit a number of diseases of
bacterial, viral, and parasitic origin. Are
spiders implicated in the transmission of any
common infectious diseases? A) yes B)
no Answer B) noCertainly none that are common.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 2

Question 2 Which of the following groups of
diseases are all transmitted by insects or
ticks? A) yellow fever, Lyme disease, typhoid
fever B) syphilis, gonorrhea, AIDS C) Rocky Mt.
spotted fever, typhus, viral encephalitis D)
rabies, viral encephalitis, Lyme disease E)
African sleeping sickness, giardiasis,
plague Answer C) Rocky Mt. spotted fever,
typhus, viral encephalitisThese come from,
respectively, ticks, fleas, and mosquitoes.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 2

Question 3 Which of the following microbes can
cause chest pain? A) influenza virus B)
Streptococcus pneumoniae C) Coxsackievirus B D)
rabies virus E) all of the above Answer E) all
of the aboveBut by different mechanisms.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 2

Question 4 Which of the following groups of
infectious diseases cause neurological changes?
A) cat scratch disease, measles, meningitis B)
AAV infection, mycoplasma pneumonia, tetanus C)
meningitis, viral encephalitis, rabies D) chicken
pox, measles, rotavirus infection E) gonorrhea,
syphilis, Herpes infection Answer C)
meningitis, viral encephalitis, rabiesAll these
are infections of the brain or brain covering and
all can cause some type of neurological change.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 2

Two days later the gentleman returned in acute
distress. He complained of a headache and also a
terrible thirst. He had a fever of 39.6,
hypersalivation, inability to swallow, and a
staggering gait. As the technician tried to
take a routine blood sample, the man tried to
bite her. The doctors and nurses stated that
they had ever seen anything quite like it.
However, a nurse from the Philippines thought
she recognized the disease immediately.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 2

Question 5 What rare disease did the nurse think
she recognized? A) encephalitis B)
leishmaniasis C) meningitis D) cysticercosis E)
rabies Answer E) rabiesThe hydrophobia,
hypersalivation, and biting behavior are all
almost unique to rabies. It is endemic in the
Philippines so the nurse might well recognize it.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 2

The doctors decided, instead, to do a spinal tap
to diagnose the man's disease. Question 6 What
diseases might they be considering when they
ordered the spinal tap? A) meningitis B)
encephalitis C) both A and B D) neither A nor
B Answer C) both A and BBoth are
possibilities.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 2

Question 7 What are the most common causes of
acute meningitis? A) Haemophilus influenzae,
Neisseria meningitidis, and Streptococcus
pneumoniae B) Listeria monocytogenes,
Escherichia coli, and Streptococcus agalactiae C)
measles, mumps, and herpes viruses D)
cryptococcus and histoplasmosis fungi E)
enteroviruses Answer A) Haemophilus
influenzae, Neisseria meningitidis, and
Streptococcus pneumoniae These three bacteria are
the most frequent causes of meningitis.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 2

The lab results on the blood and CSF evaluation
showed the following CSF 2 red blood cells, 1
neutrophil, and 9 lymphocytes/ml CSF glucose 67
mg/dL (normal 40-80) CSF protein 163 mg/dL
(normal 15-45) CSF gram stain negative Blood
count 12,100 leukocytes/ml Blood glucose 98
mg/dL
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 2

Question 8 The CSF glucose and protein profile is
most characteristic of? A) bacterial
infection B) viral infection C) fungal
infection Answer B) viral infectionCSF protein
is slightly high and glucose is normal. This is
indicative of a viral infection. The lymphocytes
also are indicative of a virus. Based on the
analysis of the CSF and the negative Gram stain,
the doctors decided he had a viral encephalitis.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 2

Question 9 EEEV, WEEV, VEEV and St. Louis
Encephalitis virus all cause encephalitis. How
are these viruses transmitted? A) from horses B)
by bird droppings C) by mosquitoes D) by
mosquitoes or ticks E) via the respiratory route
from other infected humans Answer C) by
mosquitoesThe mosquitoes transmit it from the
birds to humans. Note Two types of
encephalitis are transmitted by ticks, but not
the four listed here.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 2

While in the hospital, his condition rapidly
deteriorated, and even though he was placed on
respiratory support he died the next day.
Brain specimens were sent to the Department of
Pathology where rabies was diagnosed on the basis
of Negri bodies and detection of rabies antigen
by a positive reaction after staining with
fluorescent anti-rabies antibody.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 2

Subsequent correspondence with his family in
Mexico revealed that a puppy had bitten him on
the neck two weeks before he came to Florida
(i.e., about six weeks ago). He had thoroughly
cleaned the bite site and because it was not
deep, he had not worried about it. The family
stated that the puppy had been taken to another
neighborhood and abandoned because it had tried
to bite both humans and other animals.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 2

Question 10 What behavior occurs in rabies that
does not occur in other viral encephalitides? A)
excessive salivation B) hydrophobia C) biting
(snapping) D) all of the above E) none of the
above Answer D) all of the aboveYes, they all
do.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 2

Question 11 How did the man get rabies? A) the
spider bite B) the puppy bite C) the drinking
water in Mexico D) via the respiratory route E)
from a corneal transplant Answer B) the puppy
biteAny mammal can transmit rabies, but dogs are
a very common source, especially in
underdeveloped countries. In Florida it is
usually raccoons. People have also gotten rabies
from a corneal transplant. Several times in
fact. But the patient didn't have a corneal
transplant that we know of. Furthermore, there
is usually periorbital pain with
corneal-transmitted rabies.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 2

Question 12 How could the man's rabies have been
prevented? A) vaccination prior to the bite B)
vaccination after the bite C) prophylactic
interferon after the bite D) hyperimmune
globulin E) B and D Answer E) B and
DPost-exposure vaccination works with rabies
because of the long incubation period. However,
hyperimmune serum globulin is also given in the
case of a bite by a possibly rabid animal.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 2

Question 13 Who discovered that rabies could be
prevented by post-exposure vaccination? A)
Salk B) Sabin C) Jenner D) Koch E)
Pasteur Answer E) PasteurIt was almost 100
years after the world's first vaccine for humans
(Jenner's smallpox vaccine) that Pasteur
developed the second--rabies.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 2

Question 14 What other viruses are in the same
family as rabies? A) EEEV B) Lyme disease
virus C) California Encephalitis virus D) Norwalk
virus E) none of the above Answer E) none of
the aboveVesicular Stomatitis virus (VSV) is in
the same family as rabies, the rhabdoviruses, but
it mostly just causes disease in cows. It is
used, however, as a model to study rhabdoviruses.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Study 2

Outcome Twenty health care workers who had
helped care for the gentleman were given rabies
vaccination. His son and daughter-in-law also
received it. None of the known contacts became
sick. Health authorities in Mexico were
notified and administered vaccine to 4 children
who had reportedly played with the dog. The
abandoned puppy was never found, but they
identified a 10-block area in which all owned
dogs were vaccinated and all strays were
destroyed. No other cases were reported.
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Bugs, Drugs, and Thugs

• Infectious Disease Case Review Scorecard

So. How did you do? Add up your correct of
answers. 29 - 30 Correct You must have your
Ph.D.! 27 - 28 Correct You must be working on
your Masters Degree! 25 - 26 Correct You must
be a Lab Technician 22 - 24 Correct You must
be an Administrator 19 - 21 Correct You must
be a Lab Commander 16 - 18 Correct You must be
doing a lot of PT! 15 or less Correct You must
be a Physician!