Case Study Infections of the Cardiovascular and Lymphatic System Toxoplasmosis……………..Don’t Blame Fluffy! As part of their commitment to “going green,” Layla and Steve Jackson lived on a small farm in rural northwest Pennsylvania. Steve chopped wood from their forest to burn in their Franklin stove, and about 25% of their electricity was generated by the wind turbines on top of their mountain. They raised almost all of their own food between their small apple orchard, huge vegetable garden, and a berry patch. The couple reared numerous sheep, a few pigs, and one dairy cow. These animals plus the rabbit, turkey, and deer Steve hunted more than covered their meat and milk needs. Although the young couple loved working their farm, to make ends meet financially, they also taught at the local high school. Layla was a 10th grade math teacher and Steve served as both the choral and band directors for grades 7–12. Unless the roads were icy in the winter, the “green team” biked the four miles to work every day. While this lifestyle kept them extremely busy, Layla and Steve felt great satisfaction knowing their carbon footprint was significantly less than that of the average American. As Layla picked the green beans and weeded around the squash one July morning, she pondered how their lifestyle would change in November when their first child was due to be born. She was pleased to be able to raise their child in the unpolluted environment of their country farm and nourish him with homegrown foods free of the pesticides and preservatives found in many commercially produced items. “Of course,” Layla said to herself while patting her belly, “I think we’ll have to break down and drive a little more this winter. You’ll be a bit too small for my baby bicycle seat.” As if on cue, the baby started “dancing.” Laughing, Layla collected the baskets of produce she had harvested and headed to the kitchen to start making lunch. After rinsing the fresh-picked fruits and vegetables, Layla used her garden’s bounty to assemble a delicious salad and homemade strawberry shortcake with cream from Josie, their cow. Later that afternoon, the couple went to Dr. Schneider’s office for Layla’s monthly prenatal examination. They watched with amazement as the obstetrician used ultrasound to measure the baby’s growth, confirming that Layla was 23 weeks pregnant. Dr. Schneider pointed out different features of their developing child. They saw a tiny beating heart and learned it was time to paint the nursery blue! Layla’s pregnancy progressed normally until her next appointment at 27 weeks gestation. Dr. Schneider was surprised to find Layla hadn’t gained any weight in four weeks. “At this stage of your pregnancy, you should be gaining about 0.5 to 1 pound per week,” Dr. Schneider said with concern. “Are you eating enough nutritious foods?” Layla was happy to report a healthy appetite that she regularly indulged with the foods she and Steve raised. “I bet it’s the extra exercise I’m ge ...

1. Case Study
Infections of the Cardiovascular and Lymphatic System
Toxoplasmosis……………..Don’t Blame Fluffy!
As part of their commitment to “going green,” Layla and Steve
Jackson lived on a small farm in rural northwest Pennsylvania.
Steve chopped wood from their forest to burn in their Franklin
stove, and about 25% of their electricity was generated by the
wind turbines on top of their mountain. They raised almost all
of their own food between their small apple orchard, huge
vegetable garden, and a berry patch. The couple reared
numerous sheep, a few pigs, and one dairy cow. These animals
plus the rabbit, turkey, and deer Steve hunted more than
covered their meat and milk needs. Although the young couple
loved working their farm, to make ends meet financially, they
also taught at the local high school. Layla was a 10th grade
math teacher and Steve served as both the choral and band
directors for grades 7–12. Unless the roads were icy in the
winter, the “green team” biked the four miles to work every
day. While this lifestyle kept them extremely busy, Layla and
Steve felt great satisfaction knowing their carbon footprint was
significantly less than that of the average American.
As Layla picked the green beans and weeded around the squash
one July morning, she pondered how their lifestyle would
change in November when their first child was due to be born.
She was pleased to be able to raise their child in the unpolluted
environment of their country farm and nourish him with
homegrown foods free of the pesticides and preservatives found
in many commercially produced items. “Of course,” Layla said
to herself while patting her belly, “I think we’ll have to break

2. down and drive a little more this winter. You’ll be a bit too
small for my baby bicycle seat.” As if on cue, the baby started
“dancing.” Laughing, Layla collected the baskets of produce she
had harvested and headed to the kitchen to start making lunch.
After rinsing the fresh-picked fruits and vegetables, Layla used
her garden’s bounty to assemble a delicious salad and
homemade strawberry shortcake with cream from Josie, their
cow. Later that afternoon, the couple went to Dr. Schneider’s
office for Layla’s monthly prenatal examination. They watched
with amazement as the obstetrician used ultrasound to measure
the baby’s growth, confirming that Layla was 23 weeks
pregnant. Dr. Schneider pointed out different features of their
developing child. They saw a tiny beating heart and learned it
was time to paint the nursery blue!
Layla’s pregnancy progressed normally until her next
appointment at 27 weeks gestation. Dr. Schneider was surprised
to find Layla hadn’t gained any weight in four weeks. “At this
stage of your pregnancy, you should be gaining about 0.5 to 1
pound per week,” Dr. Schneider said with concern. “Are you
eating enough nutritious foods?” Layla was happy to report a
healthy appetite that she regularly indulged with the foods she
and Steve raised. “I bet it’s the extra exercise I’m getting,”
Layla explained. “I’ve been canning produce as fast as I can
harvest the garden and orchard. I’m up and down the hillside a
dozen times a day hauling a full bushel basket, so I bet I’m just
burning off the calories with my gardening.” Dr. Schneider
cautioned Layla not to be lifting heavy baskets and encouraged
her to add an afternoon snack to her usual diet. “I want to see
you in two weeks to be sure your weight gain is back on track,”
Dr. Schneider ordered. Exactly one week later, Layla called and
scheduled an urgent appointment. For the previous 48 hours,
Layla had experienced significant vomiting and diarrhea. By the
time she arrived at Dr. Schneider’s, Layla was weak and
slightly dehydrated. Frantic, Layla reported a decrease in fetal
activity. Dr. Schneider admitted Layla to the hospital for IV

3. fluids and prescribed medication to ease her GI distress.
What infections manifest with these symptoms? Are any
specifically associated with pregnancy?
An hour later Dr. Schneider performed an ultrasound to check
on the progress of Layla’s developing son and was shocked to
see no fetal growth since her week 23 examination. In the
morning, Dr. Schneider arrived at the hospital early to examine
Layla and her baby. Steve was asleep in a chair and Layla sat up
in bed weeping gently. She hadn’t felt the baby move since
midnight. Dr. Schneider confirmed Layla’s worst fears with
another ultrasound, which showed no fetal heartbeat. Labor was
induced to deliver Layla and Steve’s 28-week-old stillborn son.
A fetal autopsy revealed elevated titers of toxoplasmosis
antibodies, hydrocephalus and brain lesions.
Describe the causative agent of toxoplasmosis. Outline the life
cycle of this microorganism.
A week later, Layla and Steve met with Dr. Schneider to review
the autopsy report and answer their long list of questions. “So, I
got toxoplasmosis and that’s why I was so sick…and then I
made the baby sick too,” Layla said dismally.
Were Layla’s symptoms consistent with toxoplasmosis?
Describe the usual signs and symptoms of this infection. What
is a secondary infection?
“No,” Dr. Schneider replied, “not exactly. Your GI symptoms
were coincidental and represent a secondary infection. They
simply alerted us to the problem with the baby’s growth. It
does; however, appear you’ve been infected with toxoplasmosis
and the pathogen crossed the placenta to affect your baby.
“Wait a minute,” Steve interjected. “How did Layla get
toxoplasmosis? I’ve heard about this disease. Pregnant women

4. get it from changing litter boxes. We don’t have a pet cat. In
fact, we don’t even have strays in our barn!”
Are litter boxes a source of pathogen transmission? Explain.
What are the most common means of toxoplasmosis
transmission? Based on this information, was Layla at high risk
for infection? How can toxoplasmosis be prevented?
What is the prevalence of toxoplasmosis?
“Dr. Schneider, was there any way to diagnose and treat my
infection that might have saved our baby?” Layla asked. “There
are different diagnostic tests for toxoplasmosis, but they aren’t
routinely run in a prenatal panel in the U.S. unless we have
reason to suspect infection,” Dr. Schneider explained. “If a
pregnant woman is infected, several treatment protocols are
available, but the benefits must be carefully weighed against the
risks since the likelihood of transmission and fetal damage
varies with the gestational age of the mother seroconversion
How is toxoplasmosis typically diagnosed? What challenges are
associated with interpreting test results? How can fetal infection
be determined?
Describe the principal treatment protocols for toxoplasmosis
infection in a pregnant patient. Indicate the pros and cons of
each treatment. When is the best time during the course of
Toxoplasma gondii infection to administer treatment to a
patient?
Explain the correlation between the gestational age of maternal
seroconversion for toxoplasmosis and the risk of fetal infection.
What signs and symptoms are expressed by neonates with
congenital toxoplasmosis? What symptoms are expressed by

5. infected children within the first year of life? What is the
miscarriage rate associated with fetal toxoplasmosis?
“Now that I’ve been infected with toxoplasmosis, do I need to
be treated? If I’m cured can we still have other children, or will
I infect them too, causing another miscarriage?” Layla asked
hopefully. “Not to worry,” Dr. Schneider consoled the young
couple. “You’ve suffered a devastating loss, but I’m confident
you’ll soon be parents.”
Is it necessary to treat Layla for toxoplasmosis? Can she have
subsequent children without risking their infection?
Anderson, R. et.al. Case study in microbiology: A Personal
Approach, Publisher: John Wiley & Sons Copyright year: ©
2006.
Case Study # 4
Sex, Drugs and Rock and Roll
Jim was a police officer and his wife Barb a nurse at the
hospital that handled most of the city’s poor. It w as inevitable
that their paths would occasionally cross during work. Tonight,
they were both at a community outreach meeting concerning the
problems caused by the increase in crystal meth use.
Methamphetamine, or crystal meth, is a powerfully addictive
stimulant that has an intense euphoric
effect. Jim saw its effect when chronic crystal meth users would
embark on binges of constant meth use. The results were
universally disastrous––intense paranoia, visual and auditory
hallucinations, and violently out-of-control behavior. Barb saw
another side of abuse of the drug. Crystal meth use has a potent
effect of increasing the sex drive. As a result, crystal meth users
were more likely than others

6. to engage in high-risk sexual behaviors and have more sexual
partners than nonusers. Barb had seen a significant increase in
cases of gonorrhea in general, and increases in syphilis and HIV
disease among gay men. Long-term users of crystal meth build
up a tolerance to the drug. As a result, many choose to inject the
drug to continue to get high. Not unsurprisingly, intravenous
drug use increases the spread of HIV as users share needles (and
therefore exchange small amounts of blood). At counseling
programs designed to help HIV-positive gay and bisexual men
who use crystal meth, about half had injected meth during the
last year. Neither Jim nor Barb was the type to sit back and
hope for the best. They had much invested in their community
where their children went to school. Both were consistent
volunteers. Jim already coached soccer and led scouts. Barb was
active at their church and volunteered to help students with
reading and math at school. At the end of the meeting, both took
part in the discussion and planning sessions on how to help the
community stem the problems caused by widespread crystal
meth abuse.
What types of behaviors are considered high risk for acquiring
sexually transmitted infections?
What pathogens are responsible for causing these STI’s?
Describe each.
What are the clinical signs and symptoms of gonorrhea?
Compare them to those caused by syphilis.
What other STIs would you expect to be increased following an
increase in high-risk sexual behaviors and an increase in sexual
partners?
In general, how can the spread of STIs be reduced?

7. Are the activities needed to prevent or reduce the spread of STIs
likely to be followed by crystal meth users?
What recommendations would you make to Jim and Barb’s
community group to help reduce the spread of STIs among the
crystal meth users?
Anderson, R. et.al. Case study in microbiology: A Personal
Approach, Publisher: John Wiley & Sons Copyright year: ©
2006.