Final Exam

In an experiment, test subjects are given a diet without sucrose, while control subjects are given a
diet with sucrose. Which of the following results would NOT be expected?
A. Test subjects would have a more acidic oral pH.
B. Test subjects would have fewer Streptococcus mutans adhering to their teeth.
C. Control subjects would form a multi-species biofilm on their tooth enamel.
D. Test subjects would have a lower incidence of dental caries.
E. There would be a thicker glycocalyx on the teeth of control subjects.

Test subjects would have a lower incidence of dental caries.

Which of the following is a major virulence factor in Helicobacter pylori?
A. An antiphagocytic capsule
B. Ability to produce lots of acid
C. An AB toxin
D. The enzyme urease
E. Ability to live within macrophages

The enzyme urease

What is the most effective treatment for cholera?
A. Antibiotics as soon as the infection is apparent
B. An oral antitoxin
C. Oral rehydration with isotonic electrolyte
D. Intravenous saline drip
E. Prompt surgery to remove the diseased tissue

Oral rehydration with isotonic electrolyte

Which of the following is NOT a part of the Shigella disease cycle?
A. Forms ruffles on M cells in intestine
B. Gets uptaken by macrophages
C. Enters epithelial cells via the basal membrane
D. Spreads between cells via actin polymerization
E. Eventually colonizes the gallbladder, where it can persist for years

Eventually colonizes the gallbladder, where it can persist for years

The usual location of a mumps infection is . . .
A. lung epithelial cells
B. glandular epithelial cells
C. intestinal epithelial cells
D. macrophages
E. nerve cells

glandular epithelial cells

A 38-year-old intravenous drug user presented at a clinic with a swollen, tender abdomen. The
sclera of his eyes were yellow (icteric), and his skin had a faint yellow coloration. A direct fluorescent
antibody test was positive for a particular infectious agent. What is unusual about this agent?
A. It is transmitted as a foodborne illness, but has non-gastrointestinal symptoms.
B. Antibodies produced against it cause arthritis as a late sequela.
C. It replicates nearly as fast in the body as it does in tissue culture.
D. It is a DNA virus that needs reverse transcriptase to replicate.
E. You can detect the agent with a direct antibody test instead of an indirect test.

It is a DNA virus that needs reverse transcriptase to replicate.

Which of the following do the Hepatitis A and B viruses have in common?
A. The portal of entry by which they enter the host
B. The family of virus to which they belong
C. The location of the infection in the host’s body
D. The severity of symptoms
E. They are completely different - they only happen to share a name

The location of the infection in the host’s body

The object at the right was isolated from a patient with
diarrhea. What is it? (33-8)
A. A Giardia trophozoite
B. A flagellated bacterium like Shigella
C. The motile form of Entamoeba histolytica
D. A Cryptococcus oocyte
E. A Histoplasma spore

A Giardia trophozoite

A patient presents at a clinic in Mumbai with voluminous “ricewater stool” diarrhea. The best
treatment would consist of what?
A. Intravenous isotonic saline drip
B. Slowly sipping a solution of glucose and salts
C. Vaccination with an AB toxoid vaccine
D. An injection of passive immune globulin
E. Antibiotic therapy against the vibrio causing the disease

Slowly sipping a solution of glucose and salts

Chronic diarrhea can be caused by a trophozoite that burrows into and sometimes through the
intestinal lining, causing irritation and abscesses. Which of the following public health steps would
reduce the spread of this disease in a community?
A. Drying up pools of stagnant water
B. Controlling the rat population
C. Killing the snails which the parasite uses for part of its life cycle
D. Moving the hog feedlot farther from the town water source
E. Avoiding the use of human feces from septic tanks as fertilizer

Avoiding the use of human feces from septic tanks as fertilizer

Please use the choices below for questions 12 and 13:
A. Helicobacter
B. Cholera
C. Hepatitis A
D. Hepatitis B
E. E. coli


12. Produces the CagA and VacA exotoxins, causing inflammation and enabling it to survive at low
pH.
13. A 48-year-old male patient presents at a clinic with a fever of 39oC, jaundice and dark orange urine. His arms show needle tracks from i.v. drug abuse, and his abdomen is tender on palpation. He would probably have a high antibody titer for . . .

12. A
13. D

Which of the following is NOT a virulence factor associated with Helicobacter pylori?
A. Urease
B. the VacA toxin
C. a cellulolytic toxin
D. an IgG Fc binding protein
E. motility

an IgG Fc binding protein

This could be considered the most serious hepatitis infection, since it is chronic, causes liver
cancer and organ failure, and there is no vaccine for it.
A. Hepatitis A
B. Hepatitis B
C. Hepatitis C
D. Hepatitis D
E. Hepatitis E

Hepatitis C

Rita Colwell won the Nobel Prize for figuring out that you can stop a Cholera epidemic by filtering
water through ordinary cloth. How does this work?
A. You're filtering out the Cholera toxin.
B. You're filtering out a mechanical vector of Vibrio cholerae
C. You're filtering out the Vibrio cholerae bacteria.
D. You're increasing the pH of the water.
E. You're aerating the water, and Vibrio is an anaerobe.

You're filtering out a mechanical vector of Vibrio cholerae

This vaccine-preventable virus is worse in adults than it is in children because it can cause
inflammation of the testes and ovaries.
A. Mumps
B. Norovirus
C. Rotavirus
D. Measles
E. HPV

Mumps

This dangerous chronic infection is transmitted mainly by contaminated needles among drug users.
It causes cirrhosis after many years. There is no vaccine. It is . .
A. E. coli O157:H7
B. Typhoid fever
C. Hepatitis C
D. Campylobacter
E. Hepatitis A

Hepatitis C

The organisms shown below were isolated from frothy, foul-smelling diarrhea from a hiker on the
Appalachian Trail, who was successfully treated with metronidazole. They are . . .
(33-19)
A. Vibrio cholerae
B. Flagellated amoebae
C. Schistosomes
D. Cryptosporidium oocysts
E. Giardia trophozoites

Giardia trophozoites

All of the following are virulence factors of Helicobacter pylori EXCEPT . . .
A. Survival in phagocytes
B. Flagella
C. An enzyme that buffers the stomach pH
D. A toxin that gets your cells to secrete urea
E. A toxin that kills your cells

Survival in phagocytes

This week there was a multi-state recall of sushi from yellow fin tuna that is contaminated with
Salmonella. You didn't hear about that? You like sushi? Damn! What symptoms can you expect to
experience if you got infected?
A. Intestinal cramps and diarrhea with some blood in the stool
B. Several gallons per day of watery diarrhea
C. Guillain-Barré paralysis
D. Jaundice and abdominal pain
E. High fever, internal organ inflammation and death

Intestinal cramps and diarrhea with some blood in the stool

Jordyn is into the party scene at her college. She drinks a lot, occasionally injects drugs at parties, and has sex with three boyfriends. (Jordyn's situation is not all that uncommon, by the way.) She is putting herself at increased risk for all of the following EXCEPT . . .

A. Pelvic Inflammatory Disease

B. Hepatitis B

C. Hepatitis C

D. Mumps

E. Lower Respiratory Infections

Mumps

Infection with which of the following is more common in the US than in developing countries?
A. Cryptosporidium
B. Giardia
C. Streptococcus mutans
D. Entamoeba histolytica
E. Vibrio cholerae

Streptococcus mutans

Helicobacter pylori has all of the following virulence factors EXCEPT . . .
A. secretion of an A-B toxin that increases cAMP production
B. production of an enzyme that buffers stomach acid
C. a toxin that damages and eventually kills stomach endothelial cells
D. a form of motility that allows it to burrow into the gastric mucosa
E. a protein that induces secretion of urea from cells lining the stomach

secretion of an A-B toxin that increases cAMP production

A particular variety of _________ is engulfed by GALT macrophages but not killed. Instead
it travels within the macrophages throughout the body, causing high fever and organ failure,
eventually becoming established in the gall bladder.
A. Campylobacter
B. Salmonella
C. E. coli
D. Shigella
E. Vibrio

Salmonella

A cause of jaundice and liver inflammation, this infection normally lasts a few weeks, and
then goes away on its own. It can be prevented with a vaccine, or by avoiding food prepared
under unhygienic conditions.
A. Hepatitis A
B. Norovirus
C. Hepatitis E
D. Giardia
E. Hepatitis B

Hepatitis A

The cyst of the organism seen below is found in feces. Where would it
normally release trophozoites? (33-27)
A. In the stomach
B. In the small intestine
C. In fecally-contaminated water
D. In the colon
E. In a snail

In the colon

A 20 year-old female was seen at a local university clinic for fever, malaise and a maculopapular
rash on the palms of her hands. Upon further questioning, she revealed that she had noticed a painless
genital ulcer about a month ago, but it had disappeared and she had not worried about it. What is her
illness?
A. Measles
B. Syphilis
C. Gonorrhea
D. Herpes
E. Chlamydia

Syphilis

Why are gonorrhea and chlamydia much more serious in women than in men?
A. The symptoms are much more obvious in women.
B. The organisms can cause serious congenital problems in the fetus.
C. The organisms can ascend the Fallopian tubes and cause pelvic inflammatory disease.
D. The organisms can enter the urethra and cause urinary tract infections.
E. An infection can result in genital warts, which can cause cervical carcinoma.

The organisms can ascend the Fallopian tubes and cause pelvic inflammatory disease.

Other than signs of meningitis, which of the following is indicative of infection with Neisseria
meningitidis?
A. Respiratory distress
B. A purpuric skin rash and petechial hemorrhages
C. A drip of pus from the urethra
D. Myalgia and muscle cramping
E. Jaundice

A purpuric skin rash and petechial hemorrhages

Several campers at a summer camp in the Ozarks developed fever and jaundice, and one
experienced kidney failure. Upon investigation, it was found that the camp had been in the habit of
relaxing the "no dogs on the beach" rule. A likely diagnosis is:
A. Pasteurella multocida
B. Lyme disease
C. Leptospirosis
D. E. coli cystitis
E. Giardia

Leptospirosis

A young woman who has recently become sexually active comes to a clinic with a burning sensation
when she urinates. The urine is cloudy. There are no other symptoms. With what is she probably
infected?
A. Neisseria gonorrhoeae
B. Treponema pallidum
C. Chlamydia trachomatis
D. Escherichia coli
E. Herpesvirus type 2

Escherichia coli

This from a newspaper: "High School senior Michael Gruber, 17, took a state Regents exam
Wednesday and went to bed with flu-like symptoms that night. By Thursday morning, he couldn't move
his neck, and he had broken out in a rash. He was so ill he was taken to a local hospital. By Thursday
afternoon, he was dead." From what did this student most likely die?
A. Leptospirosis
B. Cryptosporidium
C. Bacterial meningitis
D. Brucellosis
E. Mumps

Bacterial meningitis

What is the best way to diagnose syphilis in its primary stage?
A. Culture the bacterium on selective agar and look for the distinctive colonies.
B. Look for the unique rash.
C. There will be a very painful ulcer at the site where the virus entered the body.
D. Perform an indirect ELISA with IgM rather than with IgG.
E. Perform a direct fluorescent antibody test.

Perform a direct fluorescent antibody test.

A 20-year-old sexually active male shows symptoms of mild urethritis with a clear fluid secretion
from the tip of his penis. A Gram stain of the drip does not show anything that looks like a bacterial
cell. He is embarassed and wants to decline treatment. What is the danger if he is not treated?
A. He could become sterile.
B. The virus that causes this will not go away, and he will experience reinfections.
C. He will likely give it to his girlfriend, who could experience a serious pelvic infection.
D. As his immune system is damaged, he will experience many secondary infections.
E. He could experience disfiguring or fatal autoimmune sequelae after many years.

He will likely give it to his girlfriend, who could experience a serious pelvic infection.

A prostitute in Indianapolis develops a macular rash over her entire body, including her palms and
soles, and the inside of her mouth. A direct fluorescent antigen (dFA) test for syphilis is positive. How
long has she had syphilis?
A. She just got it if the dFA test is positive
B. More than a week, but less than a month
C. More than a month, and maybe for a few years
D. At least 5 and maybe as many as 20 years
E. There is no way to determine this from the limited information given.

More than a month, and maybe for a few years

Mary returns from class to find her roommate, Jill, dazed and disoriented with a high fever, stiff
neck and purple, blotchy rash. What should be done?
A. Jill should be watched for 24 hours to make sure she doesn’t get worse.
B. Jill should go to the student health clinic and get a course of antibiotics.
C. Jill should go to the clinic for antibiotics and should tell her sexual partner to get
checked for STDs.
D. Mary should call 911, and Jill will need surgery to remove infected tissue.
E. This is a major medical situation. Jill needs to be hospitalized immediately, and
everyone in the dorm needs to take antibiotics to avoid getting what she has.

This is a major medical situation. Jill needs to be hospitalized immediately, and
everyone in the dorm needs to take antibiotics to avoid getting what she has.

In addition to causing urethritis and vaginitis, which sexually transmitted diseases are well known
for causing pelvic inflammatory disease in women and substantially increasing the likelihood of
sterility or ectopic pregnancies?
A. Trachoma and Chlamydia
B. Candidiasis and Gonorrhea
C. HPV and Herpes
D. Chlamydia and Gonorrhea
E. Syphilis and HPV

Chlamydia and Gonorrhea

A woman in her 35th week of pregnancy comes to a clinic with genital blisters, which she says itch
badly and cause a burning sensation. Examination reveals several clusters of small encrusted and
ulcerated blisters. She has had these same symptoms before. What should be done?
A. Prescribe penicillin to treat the infection.
B. Vaccinate her for HPV infection.
C. Suggest that she consider having her baby delivered by C-section.
D. Do an ultrasound to check for potential fetal malformation.
E. Give the baby tetracycline or silver nitrate eye drops when it is delivered.

Suggest that she consider having her baby delivered by C-section.

A serious inflammation of the Fallopian tubes that can lead to tubal scarring and sterility or
problems during pregnancy is quite frequently associated with . . .
A. Chlamydia and Gonorrhea
B. Primary and Secondary Syphilis
C. Herpes and Chlamydia
D. Several types of Human Papillomavirus
E. Neisseria gonorrhoeae and Neisseria meningitidis

Chlamydia and Gonorrhea

A 20-year-old sexually active male noticed an unusual rash on the palms of his hands. A few
months ago he had developed a hard, painless spot on his tongue, but he didn't think it was anything
serious and it went away. How should his illness be treated?
A. An immunoglobulin shot should be given to block toxins produced by this organism.
B. He should be started on a long-term course of multiple antibiotics.
C. He should be treated for both syphilis and gonorrhea, which are often found together.
D. He should be given a single shot of penicillin.
E. It is too late to treat his illness at this stage.

He should be given a single shot of penicillin.

An infection with HSV-2 is treated with acyclovir. What is the goal of this therapy?
A. To prevent the virus from establishing a latent state
B. To destroy the latent provirus within neurons
C. To reduce the number of virions produced by a replication cycle
D. To prevent the recurrence of symptoms and cure the infection
E. To prevent secondary infections with other viruses of the same family

To reduce the number of virions produced by a replication cycle

Chlamydia and Gonorrhea are common causes of urethritis in the United States. They are
considered especially dangerous because they . . .
A. have a latent form that can cause cervical cancer in women
B. can cross the placenta to cause congenital malformations in the fetus
C. can also be transmitted asymptomatically by salivary droplets
D. are very difficult to treat, requiring long-term administration of multiple antibiotics
E. frequently cause permanent inflammatory damage to the female reproductive organs

frequently cause permanent inflammatory damage to the female reproductive organs

The earliest sign of an infection with syphilis is . . .
A. a hard, painless ulcer at the site of infection
B. a high fever and unusual rash
C. a series of painful blisters at the site of infection
D. a drip of yellowish pus from the tip of the urethra
E. granuloma formation and associated soft tissue damage

a hard, painless ulcer at the site of infection

What is leptospirosis and how do you get it?
A. A parasitic liver infection from fecally-contaminated water
B. A urinary tract infection common in women due to the shorter urethra
C. A latent viral infection you probably got the first time when you were a child
D. An STI acquired by unprotected sex with an infected partner
E. A kidney infection from contact with water contaminated by animal urine

A kidney infection from contact with water contaminated by animal urine

Two common STIs can be asymptomatic, but frequently cause painful urination, and in women
cause Fallopian tube damage and pelvic inflammatory disease. Because they are often co-infections,
they are always treated together. They are . . .
A. Syphilis and Gonorrhea
B. Herpes and Syphilis
C. Chlamydia and Gonorrhea
D. Papillomavirus and Chlamydia
E. Herpes and Papillomavirus

Chlamydia and Gonorrhea

A patient went to a health clinic with the genital infection seen at the
right. What can you say about the cause of this rash? (34-21)
A. It is an autoimmune presentation of another infection.
B. It can be transmitted across the placenta and infect the fetus.
C. It began as a hard, painless genital ulcer a while ago.
D. It can only be transmitted in moist environments.
E. It is latent in neurons, and re-infects by anterograde transport to the skin.

It is latent in neurons, and re-infects by anterograde transport to the skin.

Which of the following is NOT among the top 5 STIs in the US?
A. Herpes
B. Syphilis
C. Trichomonas
D. Papillomavirus
E. Chlamydia

Syphilis

A 20-year-old Purdue student was found by his roommate in a comatose state. He was hard to
wake up, and when he did, he rambled incoherently about a really bad headache and stiff neck. His
arms were covered with small purple hemorrhages. What is most likely wrong with him?
A. He has cystitis
B. He has malaria
C. He has bacterial meningitis
D. He has necrotizing fasciitis
E. He is infected with West Nile Virus

He has bacterial meningitis

You work at a public clinic. A patient comes to you with a cluster of painful, fluid-filled blisters on
his penis. He says this is the third time in the past year that he has had this same thing. What would
you tell him?
A. It's likely syphilis, and it can't be treated.
B. It's likely Chlamydia, and it won't bother him, but he should tell his girlfriend(s).
C. It is Papillomavirus, and he is getting reinfected each time he changes sexual partners.
D. This is the first stage of an HIV infection, and he should start on HAART right away.
E. This is Herpes. It will always be in his cells, and will recur from time to time.

This is Herpes. It will always be in his cells, and will recur from time to time.

Leptospirosis is an important disease in dogs. How do dogs get it?
A. By respiratory droplet transmission from other dogs in kennels
B. By eating infected meat
C. By getting too close to infected humans
D. By contact with contaminated urine
E. From being bitten by an infected tick

By contact with contaminated urine

Why is gonorrhea considered to be such a serious disease?
A. A toxin can be released that damages the kidneys.
B. Even asymptomatic infections can cause salpingitis and sterility.
C. It is almost untreatable due to antibiotic resistance.
D. It can cause meningitis in addition to reproductive system infections.
E. It almost always causes very painful symptoms.

Even asymptomatic infections can cause salpingitis and sterility.

A woman had multiple sexual partners while she was in college. She is now 23, and five months pregnant with her first child. She developed a fever with a rash like the one shown at the right. What is this, and why is it a problem?
A. It is meningitis. She may die from it if it isn't treated
quickly.
B. It is syphilis. At this stage of the infection, it can't be
treated.
C. It is syphilis. She can be treated, but her fetus may have been harmed already.
D. It is Chlamydia. If not treated soon, the baby may be born blind.
E. It is Chlamydia. It may cause a pelvic infection that will result in loss of the baby.

It is syphilis. She can be treated, but her fetus may have been harmed already.

What do Herpes and Varicella-Zoster Virus have in common?
A. Both have a latent stage in neurons
B. Both can integrate into the host's DNA as proviruses
C. Both cause warts, but in different locations
D. A vaccine is available for both
E. Both are considered to be STIs

Both have a latent stage in neurons

Because of anatomical differences, ______ is far more common in women than in men.
A. Gonorrhea
B. Cystitis
C. Syphilis
D. Leptospirosis
E. Herpes Simplex Virus 2

Cystitis

Which set of symptoms seen in a roommate should prompt you to call 9-1-1 for suspected
meningitis?
A. Diarrhea, headache and back pain
B. Cough, muscle soreness and fever
C. Disorientation, stiff neck and purple skin rash
D. Circular skin rash, rapid heartbeat and profuse sweating
E. Headache, nausea and vomiting

Disorientation, stiff neck and purple skin rash

A sexually active college male notices a hard but painless sore on his penis. Remembering Bio
221, he knows he needs to see a Doctor. What is the Doctor likely to do?
A. Give him a vaccine and an immune globulin
B. Give him azithromycin pills to take orally
C. Also treat him for Gonorrhea, which is a related virus
D. Give him a shot of penicillin
E. Unfortunately, there is no treatment at this stage of the disease.

Give him a shot of penicillin

Why can you never get rid of Herpes?
A. It lives in your skin cells for many years.
B. There is an autoimmune form of the disease even when the virus disappears.
C. It causes viremia and can be distributed everywhere in your body.
D. It is so common that you're sure to get it again.
E. It exists as a plasmid in the nucleus of your nerve cell bodies.

It exists as a plasmid in the nucleus of your nerve cell bodies.

What typically is the eventual cause of death from AIDS?
A. The virus spreads from the blood to other organs and causes organ failure.
B. Hyperactive TC cells eventually damage muscle and brain tissue.
C. The loss of T-cells results in secondary opportunistic infections.
D. B cells are stimulated to produce autoimmune antibodies.
E. Infected T cells proliferate uncontrollably, causing a fatal blood disease.

The loss of T-cells results in secondary opportunistic infections.

What is/are the cellular receptor(s) to which the HIV-1 virus binds?
A. CD4 AND CCR5
B. CD4
C. gp120 AND gp41
D. gp120
E. env

CD4 AND CCR5

Which of the following is true about the HIV virus?
A. It mainly affects cellular immunity rather than humoral immunity.
B. Very few people experience any symptoms right after infection.
C. There is currently no way to reduce HIV titer in an infected patient.
D. It is a naked virus that can persist for a long time on contaminated surfaces.
E. There is more than a 25% chance of acquiring it from a single sexual encounter.

It mainly affects cellular immunity rather than humoral immunity.

The HAART treatment for HIV infection involves . . .
A. an inhibitor of viral uncoating
B. a protease inhibitor and two reverse transcriptase inhibitors
C. directly observing the patient swallow the pills
D. a non-nucleoside reverse transcriptase inhibitor and a recombinant vaccine
E. filtering the virus out of the patient’s blood and returning the blood to the heart

a protease inhibitor and two reverse transcriptase inhibitors

A different HIV test is used on donated blood than is used to determine if a person is HIV-positive.
It is more sensitive, but has too many false positives. What is the test used for donated blood?
A. Western blot
B. electron microscopy
C. immunoelectrophoresis
D. indirect ELISA
E. direct ELISA

indirect ELISA

Which of the following is true about HIV infection?
A. There is more than a 10% chance of acquiring it from a single sexual encounter.
B. HIV viral titer is highest in the first months following the initial infection.
C. It mainly affects humoral immunity; cellular immunity remains intact.
D. The virus can only infect lymphoid cells, and binds to a single receptor, CCR5.
E. Hyperactive NK cells eventually damage muscle and brain tissue, causing death.

HIV viral titer is highest in the first months following the initial infection.

Place the following steps in HIV infection in the correct order.
1 - Viral genetic material integrates into the host's DNA
2 - Viral RNA is reverse transcribed
3 - A viral polyprotein is processed by a protease
4 - The virus is uncoated
5 - A surface glycoprotein binds to a receptor
A. 5 - 4 - 2 - 1 - 3
B. 3 - 4 - 5 - 2 - 1
C. 4 - 5 - 3 - 1 - 2
D. 4 - 5 - 2 - 1 - 3
E. 5 - 1 - 3 - 2 - 4

5 - 4 - 2 - 1 - 3

n treating HIV, the goal of HAART is to . . .
A. Cure the patient
B. Increase the number of TC cells
C. Prevent integration of the proviral form of HIV into the patient’s cells
D. Increase the patient’s antibody titer against HIV
E. Prevent viral replication and assembly and reduce viral load

Prevent viral replication and assembly and reduce viral load

The env gene of HIV is required for . . .
A. formation of the viral capsid
B. processing the polyprotein
C. integrating the viral DNA into the host genome
D. binding of the virus to CD4 and CCR5 receptors
E. making viral DNA copies from its RNA genome

binding of the virus to CD4 and CCR5 receptors

The goal of HIV treatment with Atripla is to . . .
A. reduce TH cells to fewer than 200/l to deprive HIV of a place to replicate
B. prevent HIV from reverse transcribing its RNA
C. enhance antibody production against HIV spike glycoproteins
D. limit viral titer to 10,000 virus per ml of blood serum
E. excise the HIV provirus from the human host’s genome

prevent HIV from reverse transcribing its RNA

According to the graph at right . . . (35-11)
A. an indirect ELISA will detect HIV infection almost
immediately
B. cytokine levels in the HIV patient should only begin to
decline after many years
C. viral titer will increase gradually as TH cell titer decreases
D. HIV begins to infect TC cells once there are no longer
enough TH cells
E. an effective HIV vaccine would have to induce cellular rather than humoral immunity

an effective HIV vaccine would have to induce cellular rather than humoral immunity

Which of the following best represents the position
of the gp120 protein in the structure of an HIV virus?
(35-12)
A. A
B. B
C. C
D. D
E. E

A

Which of the following best describes what is happening in a person (call him Mr. X) two weeks
after infection with HIV?
A. Virions have begun to grow in Mr. X's blood, but his immune system has not encountered
them yet.
B. Mr. X's TH cell numbers have begun to decline as the virus starts killing them.
C. The virus is mainly in Mr. X's macrophages. Antibodies are fighting it, but not T cells yet.
D. Mr. X's anti-HIV antibody titer has peaked. He will never have this many antibodies again.
E. Mr. X may think he has the flu or mono, with muscle aches and swollen lymph nodes.

Mr. X may think he has the flu or mono, with muscle aches and swollen lymph nodes.

What is usually the eventual cause of death for an AIDS patient?
A. HIV titer begins increasing again, and the virus starts killing more and more cells.
B. TH titer becomes too low to sustain an immune response, and other infections occur.
C. HIV begins infecting cells other than T cells, causing a host of secondary symptoms.
D. Anti-HIV antibody titer becomes so high that antibodies begin attacking self cells.
E. Since it is an RNA virus, HIV eventually mutates to a lethal form that kills the patient.

TH titer becomes too low to sustain an immune response, and other infections occur.

Why has it proven so difficult to develop a vaccine that is effective against HIV?
A. HIV binds to T cells, but not to B cells, so it is hard to make antibodies against it.
B. The vaccine virus is too small to elicit an immune response.
C. A cellular immune response is needed, but it would take a live vaccine to achieve this.
D. The virus weakens the immune system so much that the vaccine cannot induce immunity.
E. The HIV virus is surrounded by a capsule, and lacks antigenic surface proteins.

A cellular immune response is needed, but it would take a live vaccine to achieve this.

Which part of the HIV virus is encoded by the env gene
and is important for attachment to CCR5? (35-16)
A. A
B. B
C. C
D. D
E. E

A

What part of the immune system is mainly responsible for
fighting the initial stage of HIV infection?
A. NK cells
B. TH cells
C. IgM
D. TC cells
E. the Complement Cascade

TC cells

What is Toxoplasma gondii?
A. A viral STD that is commonly a co-infection with HIV
B. A bacterium that causes cat-scratch disease
C. A mechanical vector that transmits a virus from cats to humans
D. A protozoan whose cysts can be inhaled or ingested to cause opportunistic infections
E. A fungal neurotoxin that causes a type of cancer called Kaposi Sarcoma

A protozoan whose cysts can be inhaled or ingested to cause opportunistic infections

Which of the following correctly depicts the course of a typical infection with HIV? (35-19)

A

The diagram at the right represents the HIV virus.
Which structures are encoded by the gag gene?
A. Structures A and F
B. Structures C and D
C. Structures B and F
D. Structures A, D and E
E. Structures B and C

Structures C and D

What is currently the best treatment for HIV infection?
A. Nucleoside analogs and protease inhibitors that prevent viral replication within T cells.
B. An immune globulin that substantially reduces viral titer in the blood.
C. Immunosuppressive drugs that kill infected TH cells before the virus can replicate in them.
D. Reverse transcriptase inhibitors that prevent the virus from performing proviral insertion.
E. There is currently no treatment for HIV, but we're hoping
for a vaccine soon.

Nucleoside analogs and protease inhibitors that prevent viral replication within T cells.

Which part of the HIV virus shown at the right is labeled
INCORRECTLY. (35-22)
A. The structures encoded by the gag gene
B. The structure encoded by the env gene
C. The structures encoded by the pol gene
D. The ssRNA genome
E. gp120

The structure encoded by the env gene

What is the role of CCR5 in an HIV infection?
A. It is a spike protein on the surface of the virus.
B. It is one of the drugs that is used to treat the infection.
C. It is the main type of cell that the virus infects.
D. It is important for processing the polyproteins during virus assembly
E. It is one of the cellular receptors to which the virus binds.

It is one of the cellular receptors to which the virus binds.

Why is there no HIV vaccine yet, even though many people have tried to make one?
A. The virus has no antigenic surface proteins.
B. The virus has mechanisms to avoid detection by B cells.
C. The virus can undergo antigenic shift as well as drift.
D. The TC cells that fight the infection are only stimulated by a live vaccine.
E. Viral titer remains too high after initial infection for a vaccine to work well.

The TC cells that fight the infection are only stimulated by a live vaccine.

Which of the following is NOT required for HIV entry into host cells?
A. gp120
B. CD4
C. integrase
D. the viral envelope
E. CCR5

integrase

We said that HIV is a "slow" virus. What is most responsible for keeping the rate of HIV
replication low after the initial acute retroviral syndrome?
A. Interferon ab
B. TC cells
C. TH cells
D. antibodies
E. the complement system

TC cells

What is currently the main treatment for HIV infection?
A. drugs that stimulate the immune response to try to keep T cell numbers high
B. allosteric reverse transcriptase inhibitors
C. removal of the provirus from host cells
D. one pill containing three drugs that have at least 2 different modes of action
E. There is currently no treatment for infection with HIV.

one pill containing three drugs that have at least 2 different modes of action

An infection of B cells that causes swollen lymph nodes, is transmitted in saliva and can be detected
by the presence of heterophile antibodies:
A. Mononucleosis
B. Yellow Fever
C. Rabies
D. Mumps
E. West Nile Virus

Mononucleosis

Which of the following statements about malaria is NOT correct.
A. It is a sporozoal disease transmitted by mosquito bite.
B. The most serious form can recur periodically for many years.
C. An important part of its life cycle must occur in the gut of the mosquito.
D. Acute symptoms (chills, fever, sweat) are caused by lysis of red blood cells.
E. Chronic infections can result in liver damage because a form of the parasite infects
liver cells.

The most serious form can recur periodically for many years.

A foodborne pathogen that usually causes meningitis in infants and the elderly.
A. Salmonella
B. Shigella
C. Botulism
D. Bacillus
E. Listeria

Listeria

A malaria vaccine would most likely target which form of the pathogen?
A. The trophozoite, since it is frequently extracellular
B. The sporozoite, since it is the form that first enters the patient
C. The gametocyte, since it is the form that gets transmitted to the mosquito
D. The schizont, since there are so many of them
E. The merozoite, since it is the motile form of the parasite

The sporozoite, since it is the form that first enters the patient

A patient with suspected mononucleosis goes to a health clinic, where a healthcare worker performs
a mono-spot test, also called a heterophile antibody test. If the test is positive, the patient is making
antibodies against . . .
A. Epstein-Barr virus
B. Heterophile, which is a viral toxin
C. The patient’s own TH cells
D. Listeria monocytogenes
E. Ox red blood cells

Ox red blood cells

Please use the choices below for the next two questions (6-7).
A. Listeria
B. Epstein Barr Virus
C. Yellow Fever Virus
D. West Nile Virus
E. Rabies Virus
6. Has a latent form in B cells, causing B cell proliferation and heterophile antibody production
7. Zoonosis spread by mosquito bites from birds.
Mosquitoes cannot spread it between humans. Fatalities
may occur from brain inflammation.

6. B
7. D

What form of the malaria parasite is NOT found in
human red blood cells? (36-8)
A. Merozoites
B. Trophozoites
C. Sporozoites
D. Schizonts
E. Gametocytes

Sporozoites

A child was bitten by a dog. The dog was watched for 10 days, and when no symptoms developed
was released. A month later the dog died of rabies. What should be done?
A. Nothing. The child is not at risk for rabies.
B. The child should be given antibiotics to treat potential rabies.
C. The child should receive both passive and active immunization against rabies.
D. The child should have a biopsy done to look for diagnostic Negri bodies.
E. It depends on where the child was bitten (arm, leg, etc.).

Nothing. The child is not at risk for rabies.

Jim has been diagnosed with infectious mononucleosis and advised to rest for several weeks.
What is the danger if he ignores this advice?
A. Because mono replicates in T cells, Jim is susceptible to other infections.
B. Because mono is contagious by airborne transmission, Jim could start an epidemic.
C. Because mono triggers antibody production, Jim could develop autoimmune sequelae.
D. Because mono triggers lymphoid cell division, Jim could rupture his enlarged spleen.
E. Because mono is a virus, it could cause systemic viremia and Jim could die.

Because mono triggers lymphoid cell division, Jim could rupture his enlarged spleen.

Which form of the malaria parasite has enough exposure to human blood serum to make it the
target of a potentially successful vaccine?
A. Trophozoite
B. Gametocyte
C. Sporozoite
D. Merozoite
E. Zygote

Sporozoite

A baby is brought to the emergency room with extreme muscle weakness, unable to even hold her
head up. This has developed over the course of a few days. Her family was in the habit of using honey
rather than sugar as a sweetener. What would a physician expect to find?
A. Listeria toxin in the baby's bloodstream
B. Clostridial spores in the baby's lungs
C. High anti-Norovirus antibody titer
D. Clostridial colonization of the baby's intestine
E. Listeria granulomas in the baby's brain

Clostridial colonization of the baby's intestine

A vaccine must almost always be given before a patient becomes infected. But the rabies vaccine
is an exception, that is usually administered after infection. Why is it still effective?
A. There is a long incubation period while the virus is traveling to the brain.
B. The vaccine agent replicates faster that the rabies virus does.
C. The infectious agent must be present for the vaccine to induce passive immunity.
D. Antibodies bind to the Negri bodies, and a vaccine is not effective until these are produced.
E. There is some time before B cells turn into plasma cells, where the rabies virus grows.

There is a long incubation period while the virus is traveling to the brain.

At right is an abbreviated representation of the malaria life cycle.
The new malaria vaccine RTS,S was developed against which form of
the parasite.
A. The gametocyte, since it is the form that the mosquito ingests
B. The merozoite, since it is the motile form of the parasite
C. The trophozoite, since it is frequently extracellular
D. The schizont, since there are so many of them
E. The sporozoite, since it is the form that first enters the patient

The sporozoite, since it is the form that first enters the patient

An important disease in dogs and cattle, transmitted in semen and via
contaminated placental residues, this organism can also cause a human illness characterized by periodic
high fevers.
A. Pasturella
B. Bartonella
C. Toxoplasma
D. Brucella
E. Listeria

Brucella

A patient develops a sore throat with swollen lymph nodes. A precipitin test is carried
out using the patient's serum (at C), proteins from a goat (at A), and proteins from
Streptococcus (at B). The result is shown at the right. How do you explain the result?
A. The patient has Strep throat, and is at risk for autoimmune sequelae.
B. The patient has a thymus deficiency due to an autoimmune disease such as Graves' disease.
C. The patient's B cells are infected with a transforming virus like Epstein-Barr virus.
D. The patient probably has a zoonotic infection from eating cheese made from goat milk.
E. The test was done wrong; the patient's serum should have been placed at A or B.

The patient's B cells are infected with a transforming virus like Epstein-Barr virus.

A person who is bitten by a potentially rabid animal is still given a rabies vaccine, even though she
may have already been exposed to the rabies virus. Why is this done?
A. The "vaccine" is really a passive immunization to neutralize the virus, not a vaccine.
B. It takes a long time for this virus to be transported to cells in which it can replicate.
C. It takes 10 days to find out if the animal was rabid, and that's enough time to make
antibodies against the virus.
D. The vaccine mainly induces cellular immunity, which develops more quickly than humoral.
E. The vaccine is ineffective, but it is given to reassure the patient that everything possible is
being done for her.

It takes a long time for this virus to be transported to cells in which it can replicate.

You're working in a dog rescue shelter. One of the dogs you brought in last month was pregnant,
and lost her litter of puppies. She has been diagnosed with Brucellosis. What would you tell your
coworkers about this?
A. It's not a big deal – this is only a serious infection in humans.
B. If you give the infected dog antibiotics now, she won't be able to spread the infection.
C. Try to wear gloves when handling the dog, since this is transmitted by direct contact.
D. This will be a big problem. You should test all dogs, and neuter and isolate infected ones.
E. The diagnosis must be a mistake – Brucellosis is a cattle disease, not a dog disease.

This will be a big problem. You should test all dogs, and neuter and isolate infected ones.