6.6 Protists 3

Question 1

what cells do leukocytozoon infect

Answer 1

erythrocytes

Question 2

what transmits leukocytozoon and to what

Answer 2

blackflies transmit it to wild and domestic birds

Question 3

locally, which birds are highly susceptible to leukocytozoon and which are resistant

Answer 3

domestic ducks susceptible and wild ducks, especially black ducks are resistant

Question 4

what does leukocytozoon look like on a blood smear

Answer 4

the RBC nucleus is elongated and displaced to the side; females are blue and males are punk

Question 5

when is transmission of leukocytozoon highest and in what population

Answer 5

spring; to ducklings shortly after they hatch

may get high mortality

Question 6

for leukocytozoon, merogony occurs in ______________, gametogony occurs in ________________ and sporogony occurs in __________________

Answer 6

domestic ducks (in the liver and spleen); domestic ducks (in RBC); blackflies

Question 7

what cells does haemoproteus infect and in what species

Answer 7

erythrocytes of wild and domestic birds, especially birds of prey in rescues

Question 8

with haemoproteus, what stage in the host causes pathology and which is relatively benign

Answer 8

gametogony in the erythrocytes cause no damage but merogony in the endothelium, lung, liver, spleen, kidney causes problems

Question 9

how can we differentiate haemoproteus from leukocytozoon on a blood smear

Answer 9

leukocytozoon displaces the nucleus of the RBC to the side but haemoproteus looks like purple granular material filling the RBC

Question 10

what transmits haemoproteus and to what

Answer 10

midges and hippoboscid flies to wild and domestic birds (especially captive birds)

Question 11

for haemoproteus, sporogony occurs in ___________, merogony occurs in ___________ and gametogony occurs in ______________

Answer 11

midges and hippoboscid flies; wild and domestic birds (endothelium, liver, spleen, lung, kidney); wild and domestic birds (RBC)

Question 12

what is the name of the haemosporid apicomplexan parasites

Answer 12

Leukocytozoon and haemoproteus

Question 13

some flagellates infect _________ and some infect _____________ (areas)

Answer 13

mucosal sites; blood

Question 14

mucosal flagellate parasites generally _______________ and have ____________ life cycles

Answer 14

form cysts; direct

Question 15

blood borne flagellate parasites generally infect hosts (how) and have __________ life cycles

Answer 15

using vectors; complex, multi-host

Question 16

what are the 4 major groups of flagellate protists

Answer 16

diplomonads, trichomonads, amoeboflagellates, kinetoplastids

Question 17

give examples of the following:
- diplomonads (2)
- trichomonads (1)
- amoeboflagellates (2)
- kinetoplastids (2)

Answer 17

• diplomonads: giardia, hexamita
• trichomonads: trichomonas
• ameoboflagellates: histomonas, dientamoeba
• kinetoplastids: trypanosoma, leishmania

Question 18

what is the site of giardia infection

Answer 18

duodenum/upper small intestine

Question 19

what is the structure of giardia

Answer 19

8 flagella, 2 nuclei prominent ventral disk

Question 20

the giardia cyst is a rounded up ______________ with how many nuclei

what is a cyst synonymous with, if we were talking about apicomplexan parasites

Answer 20

trophozoite (2 squished together); 4 when mature

synonymous with an oocyst, we just call it a cyst now

Question 21

how can you ID a giardia cyst

Answer 21

the contents shrink away from the cyst wall and it has 4 nuclei when mature

Question 22

describe giardia life cycle

Answer 22

a cyst containing 2 trophozoites is ingested -> excysts in the host releasing the 2 trophozoites -> trophozoites divide by binary fission -> dehydration in the bowel triggers encystment -> cyst passed out in the feces

Question 23

what is the main route of giardia infection

Answer 23

fecal-oral contamination with encysted forms

Question 24

does giardia have a monoxenous or heteroxenous life cycle

Answer 24

monoxenous

Question 25

what is the main clinical sign of giardia

Answer 25

malabsorptive enteritis with foul smelling, fatty diarrhea +/- blood

Question 26

does cross-transmission of giardia between hosts occur

Answer 26

controversial

Question 27

how can we diagnose giardia

Answer 27

fecal float; IFA; trophozoites seen in diarrhea if examined in saline directly; ELISA antigen tests

Question 28

what is the primary treatment for giardia

Answer 28

metronidazole and fenbendazole; used to be a vaccine but no longer available due to limited effectiveness

Question 29

where is trichomonas found in hosts?

Answer 29

GI, urogenital organs, crop of birds

Question 30

how does trichomoniasis differ from giardia

Answer 30

no cysts formed -> direct transmission

Question 31

what is the structure of giardia

Answer 31

3-5 flagella, 1 nucleus, undulating membrane

Question 32

what is the life cycle of trichomoniasis

Answer 32

direct transmission of trophozoites -> divide by binary fission in the host

Question 33

describe the pathogenesis of trichomonas in the following species: 1) cattle 2) pigs 3) horses 4) birds

Answer 33

cattle: venereal disease (vaginitis, early abortions) pigs: non-pathogenic horses: infects cecum and colon birds: severe infections of crop and esophagus (also lower GI)

Question 34

how do you diagnose trichomoniasis

Answer 34

- direct smears looking for trophozoites - culture

Question 35

what bird species is highly susceptible to oral trichomoniasis and why? what does it resemble? how can we differentiate?

Answer 35

pigeons -> feed young using exfoliated crop epithelial cells (crop milk) resembles thrush (Candida albicans) - differentiate by how easily it comes off when you try to remove it

Question 36

what is the Histomonas meleagridis life cycle

Answer 36

divides by binary fission, no cyst, transmitted within Heterakis (cecal nematode eggs) as a paratenic host

Question 37

how does histomonas work its way up the food chain

Answer 37

trophozoites ingested by Heterakis (cecal nematodes) -> escape GI and invade the ovaries and uterus -> multiplies within nematode eggs and larvae -> ingested by earth worm -> ingested by birds

Question 38

what is the life cycle of histomonas once ingested by the bird host

Answer 38

divide in the cecae -> trophozoites penetrate the mucosa -> enter blood -> go to liver -> rapid multiplication of trophozoites in the liver

Question 39

what bird species is highly susceptible to Histomonas meleagridis

Answer 39

turkeys

Question 40

what are the lesions of Histomonas meleagridis infection (2)

Answer 40

- edematous cecum - yellow-green liver necrosis and lesions

Question 41

what are the clinical signs of Histomonas meleagridis infection

Answer 41

droopiness, ruffled feathers, hanging wings yellowish diarrhea

Question 42

how do we treat Histomonas meleagridis

Answer 42

metronidazole, management, remove soil contact, anthelmentics to remove Heterakis host

Question 43

what bird operations are most susceptible to Histomonas meleagridis infection and why

Answer 43

free-ranging due to soil contact and exposure to Heterakis (cecal nematode) which acts as the paratenic host

Question 44

what is the appearance of ciliates

Answer 44

have cilia, usually arranged in rows

Question 45

how do ciliates divide

Answer 45

binary fission; some genetic exchange by conjugation

Question 46

T/F some ciliates form cysts

Answer 46

T

Question 47

what are the two ciliate protists that cause disease in veterinary species

Answer 47

Balantidium coli and Ich multifiliis

Question 48

Balantidium coli: - where is it located - does it form cysts? if yes, appearance - replication

Answer 48

- mainly large bowel as a trophozoite - yes; has a curved, dense nucleus, and thick cyst wall - binary fission

Question 49

what species does Balantidium coli infect? is it a zoonotic risk?

Answer 49

swine; yes (ingestion of cysts)

Question 50

what are the clinical signs of Balantidium coli how can we treat it

Answer 50

- diarrhea - dysentery - abdominal pain - weight loss Tetracyclines

Question 51

Ich multifiliis host

Answer 51

- fish in aquaria

Question 52

what is the life cycle of Ich multifiliis

Answer 52

cysts containing tomites on the skin of the host -> tomite penetrates the skin and grows within the epithelium -> tomont encysts and divides forming tomites within the cyst -> cyst opens releasing tomites

Question 53

what is the infective form of Ich multifiliis

Answer 53

tomites

Question 54

where does microsporidia cause infection

Answer 54

GI tract or other MM

Question 55

what is the structure of microsporidia

Answer 55

single-celled spore with a coiled filament (extrusive tube)

Question 56

describe the microsporidia life cycle

Answer 56

spore ingested (?) by host -> infects GI tract and MM -> polar filament penetrates host cells -> asexual mitotic divison gives rise to sporoplasm -> sporoplasm divides into spores -> spores mature