Parasitology/Protozoa I

Question 1

Protozoa found in water or food contamination

Answer 1

1. Giardia lamblia (Giardiasis)
2. Entamoeba histolytica (amoebiasis)
3. Cryptosporidium (cryptosporidiosis)
4. Toxoplasma gondii (toxoplasmosis)

Question 2

Protozoa found in Insect or tick bites

Answer 2

1. Babesia microti (babesiosis)

2. Trypanosoma cruzi (Chagas disease)

Question 3

Protozoa found in contact lenses and solutions

Answer 3

Acanthamoeba

Question 4

Protozoa found in hot springs, warm water, nasal wash

Answer 4

Nagleria fowleri

Question 5

Worms (helminths) found in water or food contam

Answer 5

1. Ascaris
2. Whipworm
3. Trichinella
4. Tapeworms

Question 6

Helminths (worms found in bare feet or other soil contact)

Answer 6

hookworm

Question 7

Helminths endemic in households

Answer 7

pinworms

Question 8

Amoebiasis (entamoeba histolytica)

• Intra or extracellular?
• Sx of infnx
• Transmission?
• what form is infxous?

Answer 8

Extracellular parasit

Large bowel infxn that causes diarrhea/dysentery
- cause RBC and other cells to lyse

F-O
(also resistant to chlorination of drinking water)

Cyst (not the trophozoite or precyst)

Question 9

Most common presentation of Entamoeba pathogenesis

Answer 9

Colitis

- Amoeba can invade mucosa and erode thru lamina propria = flask shaped ulcer

Question 10

dxing Entamoeba histolytica

Answer 10

Look at stool for cysts

Serology + PCR

Immunodiagnosis

Question 11

Giardiasis

• Intra or extracellular?
• Transmission?

Answer 11

Extracellular parasite of large intestine

FO

Question 12

Most common cause of nonbacterial diarrhea in the US

Answer 12

Giardiasis

Question 13

Prevalence of Giardiasis

Answer 13

2-5% in industrialized countries

20-30% in developing countries

Question 14

Bloating, Flatulence, foul-smelling stool, fatty diarrhea

Answer 14

Giardia lamblia

Question 15

Bloody diarrhea, liver abscesses, “anchovy pase exudate”, RUQ pain, flask shaped ulcer

Answer 15

entamoeba histolytica

amebiasis

Question 16

Cryptosporidiosis

• infects small or large intestine?
• Intra or extracelluar?
• transmission?
• common sources?

Answer 16

Intestinal villus of small intestine

Intracellular parasite

FO - oocysts in water

drinking water and swimming pools (chlorine resistant)

Question 17

Clinical presentation of cryptococcus

Answer 17

Severe diarrhea in AIDS

Mild disease (watery diarrhea) in nl peepo

Question 18

Trichomoniasis

• infects what?
• Extra or intracellular?
• infects in which form?

Answer 18

Urogenital tract

• vagina & urethra in females
• urethra, sem vesicles, prostate in men

Extracellular

Trophozoite form (no cyst form)

Question 19

1 trichomoniasis complication in men and women

Answer 19

increased HIV transmission and infectivity

Question 20

Clinical presentation of trichomoniasis

Answer 20

discharge

Strawberry cervix

Question 21

Brain eating ameba, rapidly fatal meningoencephalitis

Answer 21

Naegleria fowleri

- typically lethal

Question 22

How do free living amoeba (Naegleria fowleri) get to brain?

Answer 22

travel thru olfactory nerve into frontal lobe of brain

nasal wash

Question 23

The only common pathogenic protozoan found in duodenum or jejunum

Answer 23

Giardia intestinalis
(it is a flagellate)

*so is trichomonas vaginalis

Question 24

Life cycle and pathogenesis of Entamoeba histolytica

Answer 24

Ingest cysts –>
Excyst in SI –>
Differentiating trophozoites multiply by binary fission –>
Attach to + invade Colonic mucosa –>
Can disseminate and spread via portal system –>
Liver

Question 25

Life cycle and pathogenesis of Giardiasis

Answer 25

Ingest cysts --> Excyst in stomach acid --> Trophozoites multiply in duodenum and jejunum and attach to mucosa (but doesnt invade like entamoeba)(crypt hypertrophy + villous flattening + malabsorption) --> Cysts are formed as parasites enter colon --> Comes out in Poo

Question 26

Life cycle and pathogenesis of cryptosporidium

Answer 26

Ingest OOCYSTS in water --> Release sporozoite --> Which invades small intestinal epithelial cells --> Mature asexually (shizogony) and forms merozoites --> Infect other intestinal epithelial cells Can mature sexually (gametogony) --> Forms infectious oocysts that are shed in stool

Question 27

Life cycle and pathogenesis of T. vaginalis

Answer 27

Get trophozoite via sexual transmission --> Replicates by binary fission in lower genital tract (no cyst form, and cant survive in external environment)