Protozoa 1

Question 1

an organism (parasite) that lives completely at the expense of another organism (host)

Answer 1

definition of parasite

Question 2

a relationship between two organisms in which one (parasite) gets benefit (food, physical support) from the other (host). Parasite can have minor or major effects on the survival of its host.

Answer 2

definition of parasitism

Question 3

antigen masking
antigen sharing
antigenic variation
intracellular location

Answer 3

strategies of parasites to avoid killing by host

Question 4

what are the two families under parasite?

Answer 4

protozoa and metazoa (helminths)

Question 5

sarcodina (amebas)
sporozoa (sporozoans)
mastigophora (flagellates)
ciliata (ciliates)

Answer 5

protozoa

Question 6

entamoeba histolytica
- with pseudopodia

Answer 6

sarcodina (amebas)

Question 7

toxoplasma
babesia
plasmodium
sarcocytis
cryptosporidium

• undergo sexual and asexual reproduction
• intracellular parasites

Answer 7

sporozoa (sporozoans)

Question 8

giardia
trichomonas
trypanosoma
leishmania

Answer 8

mastigophora (flagellates)

Question 9

balantidium coli

• a giant intestinal ciliate of humans and pigs
• the only human ciliated parasite

Answer 9

ciliata (ciliates)

Question 10

what are the protozoans that are not in any of the 4 groups?

Answer 10

microsporidia
- opportunistic parasites of immunocompromised patients

blastocytis
- life cycle and infectious stage remain unknown
- polymorphic shape in stool or lab culture

Question 11

flagellates, amebae, and ciliates multiply by…..

sporozoans reproduce by….

Answer 11

binary fission

schizogony (multiple fission)

Question 12

sporozoans undergo sexual recombination which leads to…

Answer 12

genomic and antigenic variation

Question 13

some parasitic protozoa able to evade host’s immune response because…

Answer 13

they are intracellular and/or undergo antigenic variation

Question 14

latent and relapse infections occur with….

Answer 14

toxoplasma gondii (tissue cysts)
plasmodium vivax
plasmodium ovale (hypnozoites in liver)

Question 15

infections by intracellular protozoa are difficult to treat because….

Answer 15

drugs must cross plasma membrane. no vaccines are available for any human parasitic disease

Question 16

a host in which sexual reproduction of a parasite takes place

Answer 16

definitive host

Question 17

a host in which asexual reproduction of a parasite takes place

Answer 17

intermediate host

Question 18

a host in which the parasite survives but without undergo further development

Answer 18

paratenic host

Question 19

a host which harbours the parasite and serves as a source of infection to other susceptible hosts. reservoir hosts do not get the disease carried by the pathogen or it is asymptomatic and non-lethal

Answer 19

reservoir host

Question 20

an organism which transmits the infection from an infected organism to a human or another organism

Answer 20

vector

Question 21

a host in which the parasite undergoes development before transmitting the parasite to another host; apply to definitive and intermediate hosts

Answer 21

biological vector

Question 22

a host in which no development of the parasite happen before transmitting the parasite to another host; apply to paratenic host

Answer 22

mechanical vector

Question 23

arthropods are the main vectors responsible for biological transmission - by biting the host

Answer 23

biological vector

Question 24

an animal that carries a pathogen from one host to another without being infected itself

eg. fly picks up pathogen from fecal matter and carries it on its body. fly transfers pathogen to food. person eats contaminated food and then gets sick.

Answer 24

mechanical vector

Question 25

risk factors: poor hygiene and sanitation limited access to clean water crowded living environment poor nutritional status low immune status age factor (too young and too old) travelling consume raw or undercooked meat or drink unboil water

Answer 25

gastrointestinal parasitic infections

Question 26

- trophozoites secrete proteolytic enzymes to invade intestinal mucose: cause flask-shaped ulcer and bloody diarrhea (dysentery) - trophozoites spread via blood from large intestine to other organs: liver (amoebic liver abscess), peritoneum, lung, and brain diagnosis: detect cysts or trophozoites in stool or tissue biopsy infectious stage: cyst

Answer 26

- intestinal amoebiasis - extra-intestinal amoebiasis

Question 27

- trophozoites attach to GI surface: malabsorption, inflammation, watery diarrhea, greasy diarrhea (fatty stool = steatorrhea; trophozoites attach on duodenal surface, impairing fat digestion and absorption) - infectious stage: cyst - diagnosis: detect trophozoites or cysts in stool, entero test

Answer 27

giardisis: gastrointestinal infection

Question 28

- a non-invasive method to obtain intestinal fluid sample (upper GI tract) for detection of Giardia lamblia and other enteric pathogens - patient swallows a string with a weighted gelatin capsule - one end of string is taped to patient's face - capsule dissolves in stomach and string is weighted at its distal end passes into duodenum - after 4hr, the string and any adsorbed gastrointestinal fluid (bile, blood, mucus) is withdrawn through the mouth - examine fluid under microscope for pathogens

Answer 28

entero test (string test)

Question 29

infect GI tract especially jejunum: - mild/self-limited water diarrhea in normal person profuse watery diarrhea, malabsorption in immunocompromised, very young or old individuals infect respiratory tract - pulmonary infiltrates with dyspnea infectious stage: oocyst diagnosis: detect spherical oocysts using acid fast stain

Answer 29

cryptosporidiosis: gastrointestinal and respiratory tract infections

Question 30

- watery diarrhea, anorexia, fatigue, weight loss, infection altered mucosal architecture and shorten intestinal villi due to inflammation - self-limited, chronic in immunocompromised people infectious stage: oocyst diagnosis: detect spherical oocysts using acid fast stain

Answer 30

cyclosporiasis: gastrointestinal infections

Question 31

- unspecific: diarrhea, abdominal discomfort, weight loss, nausea, vomiting, malaise -self-limited infectious stage: oocyst diagnosis: detect ellipsoidal-shaped oocysts in stool

Answer 31

cystoisosporiasis: gastrointestinal infection

Question 32

- intracellular protozoa which reside at small intestine of humans - cause acute gastroenteritis: diarrhea, chills, vomiting - self-limited infectious stage and transmission: - ingest sarcocysts in undercooked beef: S. hominis - ingest sarcocysts in undercooked pork: S. suihominis diagnosis: detect oocysts in stool

Answer 32

intestinal sarcocystosis: S. hominis and S. suihominis

Question 33

- ingested oocytes release sporozoites which pass through gut wall, infect endothelial cells of blood vessels and develop, then spread to muscles (skeletal, cardiac, neural tissue) to develop into sarcocysts - muscle pain, transitory oedema, fever infectious stage and transmission: ingest oocysts of non-human Sarcocystis sp. diagnosis: detect sarcocysts in muscles

Answer 33

muscular sarcocystosis: non-human sarcocystis sp. infections

Question 34

- recurrent diarrhea alternating with constipation, rarely ulcerative colitis with bloody diarrhea infectious stage: cyst diagnosis: detect trophozoites and cysts in stools

Answer 34

balantidiasis: gastrointestinal infection

Question 35

- watery diarrhea, abdominal pain, excessive flatulence diagnosis: stool examination for cyst-like or vacuole form

Answer 35

blastocystosis: gastrointestinal infection

Question 36

- by ingestion of spores in food or water - inhabit intestinal tract, causes watery diarrhea and abdominal pain

Answer 36

microsporidia

Question 37

- found at vagina, vulva, and cervix of woman - found at prostate, seminal vesicles, and urethra of man - symptoms in woman: causes vaginitis, vulva, cervix inflammation, with frothy yellow or cream-colored vaginal discharge, vaginal itching, painful urination - symptoms in man: cause prostate, seminal vesicles, and urethra inflammation, with a thin, white urethral discharge, pain after ejaculation, painful urination diagnosis: detect pear-shape flagellates in vaginal or prostate discharge

Answer 37

trichomoniasis: sexually transmitted disease