Protozoa

Question 1

Entamoeba histolytica:
Mode
Site
Diagnosis
Disease name
Other information

Answer 1

Ingestion of cysts (contaminated water, hand-to-mouth, sex)
Intestine (can be in liver lung, brain)
Cysts in feces
Amoebiasis
Cysts are nonmotile; trophozoites have pseudopod and central karyosome

Question 2

Giardia lamblia, giardia intestinalis, giardia duodenalis:
Mode
Site
Diagnosis
Disease name
Other information

Answer 2

Ingestion of cysts (outdoor water)
Intestine
Cysts in feces
Giardiasis
Trophozoites passed in stool do not survive; hard stool - cysts; soft stool - trophazoites

Question 3

Balantidum coli:
Mode
Site
Diagnosis
Disease name
Other information

Answer 3

Ingestion of cysts
Intestine
Cysts in feces
Balantidiasis
Rare in humans

Question 4

Cryptosporidium parvum/hominis, cyclospora cayetanensis, isospora belli:
Mode
Site
Diagnosis
Disease name
Other information

Answer 4

Ingestion of oocyst (water, food, swimming pool, cyclosporiasis from imported fruit)
Intestinal epithelium
Acid-fast oocysts in feces
Cryptosporidiosis, cyclosporiasis, isosporiasis
No medication (must run course); sexual and asexual in same host

Question 5

Trichomonas vaginalis:
Mode
Site
Diagnosis
Disease name
Other information

Answer 5

Direct sexual contact
Vagina, urethra
Wet mount (saline) of vaginal smear to show motile trophozoites
Trichomoniasis
Only trophozoites

Question 6

Naeglera fowleri:
Mode
Site
Diagnosis
Disease name
Other information

Answer 6

Infection of nasal passages
CNS
Trophozoite in CSF
Primary amoebic meningoencephalitis (PAM)
Aggressive (onset of symptoms in 48 hours); kills host quickly

Question 7

Acanthamoeba culbertsoni:
Mode
Site
Diagnosis
Disease name
Other information

Answer 7

Infection of skin, eye, lung, other tissues
Blood to CNS
Trophozoite in CSF
Granulomatous amoebic encephalitis
Less aggressive; cysts and trophozoites in tissue

Question 8

Trypansoma spp. (gambiense, rhodesiense, cuzi):
Mode
Site
Diagnosis
Disease name
Other information

Answer 8

Bite from vector (African - tsetse fly, American reduviid bug)
Blood plasma (African - demyelination of CNS, American - heart and GI)
Blood, lymph and CSF smear
West and East African and American tryponosomiasis (African - sleeping sickness, American - Chagas’ disease)
American mostly in South America

Question 9

Leishmania spp. (tropica, brasiliensis, donovanii):
Mode
Site
Diagnosis
Specific disease sites

Answer 9

Bite from vector (phelbotomus - sand fly)
Amstigotes in tissues
Found in macrophages
Leishmania tropica (dermal), brasiliensis (musculocutaneous), donovanii (visceral)

Question 10

Plasmodium spp.:
Mode
Site
Diagnosis
Disease name
Other information

Answer 10

Bite from vector (mosquito)
Blood and tissue
Blood smear and tests (serological ID)
Malaria
Sexual and asexual in different hosts

Question 11

Babesia spp. (microti and divergens):
Mode
Site
Diagnosis
Disease name

Answer 11

Bite from vector (tick)
Blood
Blood smear and tests (serological ID)
Babesiosis

Question 12

Toxoplasma gondii:
Mode
Site
Diagnosis
Disease name
Other information

Answer 12

Ingestion of infected meat, oocyst in food or on hands, organ transplant, blood transfusion, inoculation, inhalation, transplacental
Tissues
Serological identification
Toxoplasmosis
Definitive host - cats; intermediate hosts - humans, cattle, rodents