parasite to dx

Question 1

Giardia lamblia

Answer 1

• Examination of stool for cysts or trophozoties,

* Immunoassay to detect Giardia lamblia ags in aqueous extracts of stool samples.

Question 2

Entamoeba histolytica

Answer 2

• Look at the stool for trophozoites or cysts, only the presence of trophozoties with internalized RBCs indicates active dz.
• Best option is to use ag detection tests on the stool or serum –also allow to differentiate from the non-pathogenic bug E dispar.
• Use CAT scan or US to look for liver abscesses

Question 3

isospora and cyclospora

Answer 3

acid-fast on stool microscopy, but can also do fluorescent microscopy.

Question 4

Toxoplasma gondii

Answer 4

• CAT scan will show contrast enhancing mass.
• Retinal examination will show retinal inflammation.
• Serology: Ab titers will indicate if there has been previous exposure.

Question 5

interstitial pneumonia called pneumocystis carinii pneumonia (PCP)

Answer 5

• Silver or immunofluorescent staining cultures obtained by (in increasing yield):
o Induce sputum sample by spraying saline into the bronchioles and collecting coughed material.
o Bronchoalveolar lavage: insert a camera and wash out the deep bronchial tree with saline.
o Biopsy the lung by bronchoscopy.

Question 6

African sleeping sickness

Answer 6

microscopy of the peripheral blood, LNs, or CSF

Question 7

Naegleria fowleri

Answer 7

• CSF: high protein, low glucose and high neutrophil count, just like a bac infection
• .g stain and culture will show no bac and microscopic examination may show motile amoeba.

Question 8

chagas dis

Answer 8

Acute chagas’ dz:
• Direct examination of blood for the trypomastigotes.
• Xenodiagnosis: 40 lab grown reduviid bugs are placed on the skin to feed on the pt for a month and then their abdominal contents are examined.
Chronic chagas’ dz:
• Classic clinical findings (cardiac and megadisease) with serological evidence of past infection

Question 9

malaria

Answer 9

o Examination of blood smears on oil-immersion magnification can reveal trophozoites and schizonts inside the RBCs.
o There are also rapid ag tests that can be used, but are very expensive

Question 10

cutaneous leishmaniasis

Answer 10

skin scrapings of the ulcer base or by taking dead leishmania and placing it under the skin like PPD

Question 11

mucocutaneous leishmaniasis

Answer 11

skin scrapings

Question 12

visceral leishmaniasis kala-azar

Answer 12

• Liver and spleen biopsies.
• High leishmanial IgG levels.
• Leishmanin skin test is negative during the active dz since the cell mediated response is deficient.

Question 13

trichomonas vaginalis

Answer 13

• Microscopic examination of the vaginal discharge to find a very motile parasite.
• May also find it in the urine.

Question 14

acanthamoeba

Answer 14

CSF and brain tissue will show acanthamoeba in cyst and trophozoite stages.

Question 15

balantidium coli

Answer 15

looking for the ciliated trophozoites or cysts in the stool

Question 16

Necator americanus (hookworm) and Ancylostoma duodenale

Answer 16

Identify the eggs in a fresh fecal sample.

Question 17

Ascaris lumbricoides

Answer 17

• Look for the eggs in feces or larvae in the sputum.

* There may be an increased # of eosinophils on peripheral blood smear

Question 18

Strongyloides stercoralis

Answer 18

• Made by identifying the larvae in feces, not the eggs.
o Enterotest: long nylon string is swallowed and then brought back up later to look for the presence of larvae.
• Sputum can be examined for larvae.
• Can also do an ELIZA to look for abs.

Question 19

Trichnella spiralis

Answer 19

• Made with serologic tests or muscle biopsy that reveal the encysted larvae.
• There will be increased amount of eosinophils.
• There may also be increased amounts of muscle enzymes like CPK

Question 20

Trichuris trichiura (whipworm)

Answer 20

• (eosinophil ct not elevated since not live outside intestine)
• Look for the eggs in the stool.
• The eggs look like footballs with bumps on each end. (adults look like a bullwhip)

Question 21

enterobius vermicularis (pinworm).

Answer 21

• eosinophil ct not elevated since not live outside intestine)
• Use scotch tape to pick up the eggs in the perianal region.

Question 22

Onchocerca volvulus

Answer 22

• Look for microfilariae in skin biopsies or adult worms in a nodule.
• Can also look for the microfilariae in the cornea with a slit-lamp examination.

Question 23

Wuchereria bancrofti and brugia malayi

Answer 23

• microfilariae in blood that is drawn at night since there are very few microfilariae that circulate during the day (nocturnal periodicity)
• Can also be made by looking for abs on immunofluorescence.

Question 24

Cutaneous larval migrans (anclyostoma braziliense)

Answer 24

Biopsy of the advancing edge of the rash.

Question 25

taenia solium (pork tapeworm) when humans ingest the larvae

Answer 25

eggs or proglottids in the fecal sample.

Question 26

cysticercosis from taenia solium (pork tapeworm) when humans ingest the eggs

Answer 26

o CT/Biopsy of affected tissue (brain or muscle) that reveals calcified cysticerci.
o There are also some serological tests that can be done.
o There are increased eosinophils

Question 27

Taenia saginata (beef tapeworm)

Answer 27

gravid proglottids or eggs in the feces

Question 28

Diphyllobothrium latum (fish tapeworm)

Answer 28

eggs in the feces.

Question 29

Hymenolepis nana (dwarf tapeworm)

Answer 29

eggs in the feces.

Question 30

Echinococcus granulosus and multilocularis

Answer 30

CAT scan or biopsy

Question 31

schistosomiasis from schistosoma (blood flukes)

Answer 31

o Eggs in the stool or urine and serology for abs.

o Increased eosinophil counts, esp during katayama fever.