Deck 49: Other Protozoa

Question 1

Trichomoniasis is the primary nonviral sexually transmitted disease worldwide.One complication of this infection is:

A) keratitis.
B) endometritis.
C) meningitis.
D) appendicitis.

Answer 1

B
Trichomoniasis is the primary nonviral sexually transmitted disease worldwide.Infection with Trichomonas vaginalis has major health consequences for women, including complications in pregnancy, association with cervical cancer, and a predisposition to human immunodeficiency viral (HIV)infection.Although vaginitis is the most common finding in women with trichomoniasis, other complications include the distension of a fallopian tube with pus, endometritis, infertility, low birth weight, and cervical erosion.In addition, an increased association with HIV transmission and cervical dysplasia has been reported.

Question 2

Primates, as well as dogs, sheep, and horses, have died of central nervous system (CNS)infections with which organism?

A) Naegleria fowleri
B) Acanthamoeba spp.
C) Toxoplasma gondii
D) Balamuthia mandrillaris

Answer 2

D
B.mandrillaris is uncommon and was thought to be a harmless soil organism, with no relevance for infecting mammals.However, since B.mandrillaris was first recognized at the San Diego Wild Animal Park when a gibbon died of meningoencephalitis, a number of primates, as well as dogs, sheep, and horses, have died of CNS infection caused by this organism.Approximately 100 cases of human amebic encephalitis worldwide have been identified with approximately one-half of the cases diagnosed in the United States.Death can occur from a week to several months after the onset of symptoms.Patients eventually die with a massive CNS infection.

Question 3

Laboratory diagnosis of Trichomonas gondii is confirmed by:

A) Giemsa stain.
B) tissue culture.
C) serologic testing.
D) Western blot.

Answer 3

C
The most common method of determining a diagnosis for toxoplasmosis is serologic testing for T.gondii-specific antibodies.

Question 4

The Acanthamoeba organism is motile and has spinelike pseudopods, a single round nucleus in the cyst form, and a large karyosome in the nucleus of the troph.An estimated 70% of clinical cases of Acanthamoeba keratitis are misdiagnosed as __________ keratitis.

A) bacterial
B) fungal
C) prion
D) viral

Question 5

The CSF would reveal which of the following results in infections caused by N.fowleri?

A) Increased glucose, increased protein, and positive Gram stain
B) Decreased glucose, decreased protein, and negative Gram stain
C) Decreased glucose, increased protein, and negative Gram stain
D) Increased glucose, decreased protein, and positive Gram stain

Question 6

MATCHING
Match the infectious stage of Toxoplasma gondii with the appropriate description.
a.Crescent-shaped
b.Oocysts from cat feces
c.Tissue cysts
Tachyzoites

Question 7

Tissues suspected of containing Acanthamoeba cysts can be observed using various stains.A cyst that stains black has most likely been stained with the __________ stain.

A) methenamine silver
B) periodic acid-Schiff (PAS)
C) Giemsa
D) Wright

Question 8

MATCHING
Match the infectious stage of Toxoplasma gondii with the appropriate description.
a.Crescent-shaped
b.Oocysts from cat feces
c.Tissue cysts
Sporozoites

Question 9

MATCHING
Match the infectious stage of Toxoplasma gondii with the appropriate description.
a.Crescent-shaped
b.Oocysts from cat feces
c.Tissue cysts
Bradyzoites

Question 10

The troph of the motile Trichomonas vaginalis organism measures 7 to 23 microns long and 5 to 15 microns wide.The recommended treatment of choice for this urogenital infection is:

A) tetracycline.
B) metronidazole.
C) penicillin.
D) ketoconazole.

Question 11

A 26-year-old woman has an odorous vaginal discharge, lower abdominal pain, and difficulty urinating.Vaginal secretions are collected and sent to the laboratory for examination 3 hours after collection.No motile organisms are observed on the wet preparation; however, Trichomonas vaginalis is suspected.Which one of the following statements explains this discrepancy?

A) The infection is most likely bacterial; therefore a Gram stain should have been performed.
B) The specimen should have been refrigerated before examination; consequently, the organism was compromised.
C) The time between collection and the microscopic examination was prolonged, resulting in loss of motility.
D) No discrepancy is present; this organism in nonmotile.

Question 12

A 15-year-old male was diving in a lake when he inhaled some of the stagnate water.Five days later he was admitted to the hospital, comatose and in critical condition.A cerebrospinal fluid (CSF)specimen was taken, and several motile amoebae were observed.The patient would most likely be diagnosed with which of the following conditions?

A) Granulomatous amebic encephalitis
B) Primary amebic meningoencephalitis
C) Secondary amebic encephalitis
D) Chronic granulomatous meningitis