Intro to Parasites

Question 1

Protozoa

Answer 1

unicell organisms

considered first animals

Question 2

metazoa- helminthes

Answer 2

multicell organisms

Question 3

Entamoeba histolytica
Amoeba
Protozoa

Answer 3

Poor sanitary conditions, world wide, found in feces
Contaminated food/water, hands to mouth, sexual
Found in colon, lungs, liver, brain

Question 4

Giardia

Intestinal Flagellate

Answer 4

Found in feces
Contamination of water, food or hands/ fomites with infective cysts
Ingested into mouth

trophozoites also passed in stool but don’t survive in environment

Question 5

Balantidum coli

Intestinal Ciliate

Answer 5

Common animal parasite
Cyst found in feces
Infectious stage, acquired through ingestion of contaminated food or water

Some trophozoites invade wall of colon.

Question 6

Intestinal Sporozoa

Isospora belli
Cyclospora cayetanensis
Cryptosporidium parvum/hominis

Answer 6

Ingestion of oocyst
Infection of intestinal epith
Sexual & asex stages
Self limiting in immunocompetent
Sporogony/shcizogony

Question 7

Intestinal Sporozoa

Answer 7

Found in feces
Contamination of recreational water and food with oocytes OR drinking water
Thick walled oocyte ingested by host.

Question 8

Urogenital Flagellate

Trichomonas vaginalis

Answer 8

Trophozoite in vaginal & prostatic secretion & urine
Sexual intercourse
Found in vagina or orfice of urethra

Question 9

Amoeboflagellates (CNS pathogens)

Naegleria fowleri

Answer 9

Cysts found in water mature to trophozoits and then become flagellated in CSF!

Enter through olfactory neuroepithelium causing meningoencephalitis

Question 10

Amoeboflagellates (CNS pathogens)

Acanthamoeba culbertsoni
Balamuthia mandrillaris

Answer 10

Cysts in water, become trophozoites in tissue

Enter through lower resp tract or through ulcerated or broken skin. Casue granulomatous amebic encephalitis in people w/ compromised immunity

Question 11

Hemoflagellates

Trypanosoma & Leishmania

Answer 11

insect born flagellates

In blood, tissue, lymph & CSF

Question 12

Trypanosoma

Answer 12

T. gambiense= tsetse fly W Africa

T. rhodesiense= tsetse fly, E Africa

T. cruzi= reduviid bug, Americas
Chagas disease

Question 13

Trypanosoma

Answer 13

Tsetse fly takes a blood meel & injects trypomastigotes
Transform in bloodstream to trypomastigotes
Multiple to various body parts

Question 14

Trypanosoma cruzi

Answer 14

Tiatome bug takes a blood meal, take a dump and by scratching, humans inject the trypomastigote into wound

Penetrate and transform

Multiply in infected tissues & infect other cells

Intracellularly transform again and burst out of the cell to enter the blood stream.

Question 15

Leishmania

Answer 15

Phlebotomine sand fly

Dermal/cutaneous form
Mucocutaneous form
Visceral Form

Question 16

Tissue sporozoa

Answer 16

Plasmodium spp.- malaria
Babesia spp.- babesiosis
Toxoplasma gondii- toxoplasmosis

Question 17

Malaria

Answer 17

Mosquito takes a blood meal inject sporozoites
Infected liver cell, create schizont which ruptures
Content of bug can infect RBC, mature into trophozoite
Forms shizont and ruptures again
OR
From mature trophozoite form gametocyte which replicate

Question 18

Babesiosis

Answer 18

Tick vector

Question 19

Toxoplasma gondii

Answer 19

Ingest infected meat
Oocyte in food
Oocyte in hand, nail
Organ transplant
Blood transfusion
Accidental innoculation
inhalation
transplacental

Question 20

Toxoplasmosis

Answer 20

Cat feces or tissue cysts in cattle

Tachyzoites localize in neural & m. tissue of humans to transform into cysts
pregnant women can cross placenta