Question 1 - Single Best Answer
Why is skin testing usually not useful by itself in diagnosing endemic systemic mycoses?
A) The organisms do not elicit antibodies.
B) The organisms do not elicit cell mediated immunity.
C) Many people without disease will have positive responses.
D) By definition, when someone gets systemic infection, they failed to make an immune response.
E) None of the above - skin testing is a useful tool, in and of itself in diagnosing endemic systemic mycoses.
Question 2 - Single Best Answer
The major virulence factor and distinguishing characteristic of Cryptococcus neoformans is its
Answer:
capsule
Question 3 - Single Best Answer
A patient who was camping in Vermont in July is suffering from the "New England Summer Flu". Which of the following best describes the transmission and diagnosis of this disease?
A) transmission to humans is similar to Lyme disease; diagnosis is similar to Malaria
B) transmission to humans is similar to influenza; diagnosis is similar to Giardia
C) transmission to humans is similar to brucellosis; diagnosis is similar to Streptococcus pyogenes pharyngitis
D) transmission to humans is similar to Giardia; diagnosis is similar to Cryptosporidium parvum
E) transmission to humans is similar to Aspergillus; diagnosis is similar to Candida.
Question 4 - Single Best Answer
A 31-year-old female veterinarian complained of diarrhea that she had experienced for 2 weeks. The diarrhea was described as thin, watery, and non-bloody. The patient described 10 to 14 diarrheal stools per day, the frequency of which was not influenced by a variety of over-the-counter antidiarrheal medications. Physical examination revealed a well-developed, well-nourished woman who appeared somewhat fatigued and mildly dehydrated. The workup included a negative HIV serologic test, a normal flexible sigmoidoscopic examination, and a negative stool culture for bacterial pathogens. A microscopic examination of the stool for white blood cells was negative. A stool specimen was sent for ova and parasite examination and, after appropriate concentration measures, demonstrated acid-fast oocysts. Which statement most accurately describes the pathogenesis of this woman's disease?
A) She has a viral diarrhea.
B) A worm that looks like a whip has embedded itself into her rectum.
C) A protozoal cell invaded the mucosal epithelium.
D) Candida albicans hyphae have invaded into her epithelium.
E) Hookworms are attached to her intestinal epithelium and are sucking her blood.
Question 5 - Single Best Answer
An adult male from Mexico died from cardiac complications from a parasite that was transmitted to him by a "kissing bug". At the earliest stage of his disease, this man most likely experienced:
A) a black eschar on his neck.
B) cutaneous lesions of rash and edema on his face.
C) diarrhea.
D) a bull's eye rash on his arm or leg.
E) a high spiking fever every 36 to 48 hours.
Question 6 - Single Best Answer
Which infectious disease is transmitted by Cimex leticularis, the bed bug?
A) HIV
B) HCV
C) Malaria
D) Babesiosis
E) None of the above.
Question 7 - Single Best Answer
A pediatric patient experiences a prolapsed rectum because of heavy infection by Trichuris trichuria (whipworm). The infection will most likely be treated with:
A) Ketoconazole
B) Mebendazole
C) Trimethoprim
D) Metronidazole
E) Amphotericin B
Question 8 - Single Best Answer
A leukemia patient on chemotherapy experiences severe neutropenia (less than 100/ul). Several days later he experiences fever that did not respond to antibiotics. He then developed coughing and respiratory distress. A stained biopsy of the lung is shown in the image. This organism most likely was encountered from:
A) the man's intestinal tract.
B) eating food.
C) breathing respiratory droplets from another patient.
D) the environment.
E) the drinking water system.
Question 9 - Single Best Answer
A reason for the geographical limitation of schistosomiasis is the geographical range of the:
Answer:
snail host
Question 10 - Single Best Answer
A 38 year old HIV-positive male with a CD4 count of 80/ul had a 1 week history of progressively worsening headache, photophobia, lethargy, and fevers to 38.5C. On the morning of his admission he became confused, disoriented, and ataxic, having fallen three times. His vital signs were within normal limits. Head CT was normal. Lumbar puncture revealed 32 WBCs/ul (90% lymphocytes), low glucose, moderately elevated protein. Based on this information, the definitive diagnosis for the most likely causative agent at this point could be made by:
A) culture of the CSF on blood agar with no other tests.
B) performing a latex agglutination assay for antigens in serum or CSF.
C) performing an ova and parasite analysis of urine.
D) performing an ova and parasite analysis of CSF.
E) PCR for viral antigens in CSF.
Question 11 - Single Best Answer
Sickle cell disease is hypothesized to be prevalent in people of African ancestry because it protected against
Answer:
malaria
Question 12 - Single Best Answer
A 62 year old male had a 4-day history of swelling of the left eye and frontal headache. His family has a history of diabetes, for which he had never been tested. His blood glucose level was 500mg/dl. CT scan revealed fluid in the ethmoid sinuses, and endoscopy revealed a thick brown discharge from the sinuses and necrosis of adjacent tissues. How does the causative agent cause this disease?
A) secretes a potent cytotoxin that kills epithelial cells.
B) invades epithelial and endothelial cells and causes cytotoxicity
C) invades blood vessels resulting in occlusion of the vessels
D) stimulates autoimmunity
E) invades and replicates in red blood cells, causing them to adhere to capillary walls causing occlusion of the vessels
Question 13 - Single Best Answer
An 83 year old male with metastatic adenocarcinoma of the prostate also has end stage chronic obstructive pulmonary disease (COPD). Because of a flare-up of his COPD be was placed on antibacterial drugs and corticosteroids. Within several days of completing corticosteroid treatment he experienced nausea, vomiting, shortness of breath, and purulent, blood-tinged sputum. A wet mount of the sputum revealed the organism shown in the picture. Which organism caused his most recent respiratory symptoms?
A) Strongyloides
B) Echinococcus
C) Enterobius
D) Schistosoma
E) Trichuris
Question 14 - Single Best Answer
A 12 year old girl had cramps and abdominal pain for 1 to 2 weeks. On the day of evaluation, the girl involuntarily passed what she and her mother described as an earthworm into her underwear (see the figure). The family had never been out of the country. Which of the following best describes the journey of this worm in this girl's body?
A) Invaded the feet, migrated through blood to the lungs, coughed up, swallowed to intestines.
B) Egg was consumed, swallowed, matured to larvae and invaded intestines, blood to lungs, coughed up, swallowed to intestines as adult.
C) Larvae ingested in meat, invaded intestines, blood to lungs, coughed up, swallowed to intestines as adult.
D) Egg ingested, matured to adult on the way to intestines, stayed in intestines.
E) Larvae ingested in meat, matured to adult on way to intestines, stayed in intestines.
Question 15 - Single Best Answer
A 30 year old woman experiences dysentery-like symptoms for three weeks (visible blood, pus, and mucus in stool). The diagnosis was confirmed by observing cysts in the stool. Each of the following is consistent with this disease EXCEPT:
A) The organism secretes a cytotoxin.
B) The organism can invade to the liver.
C) This disease is treated with metronidazole.
D) Histological analysis of intestinal epithelium would reveal flask-shaped ulcers.
E) The organism adheres to the epithelium with a ventral sucker.
Question 16 - Single Best Answer
Which of the following statements MOST ACCURATELY describes the pathogenesis involved in a patient with chronic foul-smelling, watery diarrhea, with no blood or pus?
A) The worms invaded through the skin of the feet, migrated to the lungs, were swallowed and set up a chronic infection of the intestines.
B) The cercarial form of the worm was encountered in contaminated water, invaded through the skin, spread from the blood to the intestinal tract where eggs were laid.
C) Cysts were ingested in water, differentiated into trophozoites, and infected the small intestines.
D) Worms were ingested, matured in the intestines without migrating extra-intestinally, caused a chronic infection of the lower intestinal tract.
E) Tapeworm eggs were ingested in meat, attached to the small intestinal wall, and consumed significant available nutrients.
Question 17 - Single Best Answer
In the United States tapeworms are usually encountered by:
A) consuming improperly cooked meat/fish.
B) fecal contamination of water.
C) burrowing of larvae through the skin.
D) inhalation of eggs from disturbed soil (e.g., during housing construction).
E) There are no endemic tapeworm infections in the United States. All of the cases are imported from Asia.
Question 18 - Single Best Answer
An individual taking broad spectrum antibiotics comes down with a large number of erythematous lesions with white plaques in his mouth. The likely cause is:
A) Candida
B) Cryptococcus
C) Histoplasma
D) Aspergillus
E) Mucor
Question 19 - Single Best Answer
A Scotch Tape test is used to diagnose
Answer: pinworms/ Enterobius
Question 20 - Single Best Answer
Each of the following explains why Plasmodium vivax causes more severe disease than does Plasmodium falciparum EXCEPT:
A) P. vivax infects a greater range of red blood cells.
B) P. vivax has more organisms per red blood cell.
C) P vivax causes adherence of red blood cells to capillaries.
D) There is no effective treatment for P. vivax.
E) None of the above - P. vivax is not more virulent than P. falciparum.
Question 21 - Single Best Answer
A 45 year old military officer returns from duty in Iraq. He experiences a 1.5 cm diameter lesion (shown in the image) on his forearm that is erythematous with a raised border that his buddies described as looking like a pizza. The lesion has persisted for two weeks. Biopsy and histological analysis revealed mononuclear infiltrate and intracellular forms of the pathogen. He recalls having been bitten by a flying insect at the site. The man would most likely be treated with:
A) Streptomycin
B) Amphotericin B
C) Ketoconazole
D) Mebendazole
E) Gancyclovir
Question 22 - Single Best Answer
Which of the following infection-behavioral change associations for humans is NOT correct?
A) Borna virus - schizophrenia.
B) Treponema palidum - dementia
C) Toxoplasma - Women become warm and outgoing, men become jealous and suspicious.
D) Group A streptococcus - obsessive-compulsive disorder in children
E) Histoplasma - fear of dark, enclosed places
Question 23 - Single Best Answer
Trichophyton and Epidermophyton can cause symptoms that might be confused with
A) bacterial vaginosis
B) impetigo
C) strep throat
D) rabies
E) tetanus
Question 24 - Single Best Answer
A rose gardener current in her vaccinations who experiences a thorn prick while tending to her roses is at risk for
A) ringworm
B) histoplasmosis
C) sporotrichosis
D) tetanus
E) amoebiasis
Question 25 - Single Best Answer
What is the mechanism of action of fluconazole?
A) it interacts with sterols in the cell membrane
B) it is deaminated to flourouracil and incorporated into RNA
C) it inhibits sterol biosynthesis
D) it inhibits microtubular function and acts as a mitotic poison
E) it inhibits protein synthesis
Question 26 - Single Best Answer
Bladder cancer is associated with infection by which parasite (genus and species)?
Answer:
Schistosoma haematobium
Question 27 - Single Best Answer
A 4 year old girl in day care was brought to the doctor because of several lesions on her arm. They were reddish and round, slightly raised and scaling. There were a few pinpoint pustules around the edge of the lesions. The girl had no other lesions except the ones on the arm and had no other symptoms. To diagnose, you scrape the lesion and place it on a microscope slide with a drop of 10% KOH. After this you would expect to see:
A) spirochetes
B) hyphae
C) Gram-positive cocci
D) tiny worms
E) nothing would be seen, the KOH would have dissolved everything
Question 28 - Single Best Answer
Two diseases that might be associated with caves are
A) rabies and cryptococcosis
B) histoplasmosis and RMSF
C) rabies and tinea corporis
D) histoplasmosis and rabies
E) cryptococcosis and RMSF
Question 29 - Single Best Answer
Infection with which of the following would most likely to lead to a liver abscess?
A) Staphylococcus aureus
B) Strongyloides
C) Leishmania
D) Entamoeba
E) Cryptococcus neoformans
Question 30 - Single Best Answer
Intestinal blockage could occur from infection with which worm (genus name is sufficient)?
Answer:
Ascaris - Even tapeworms apparently don't cause blockage.