6.6 Protists 3 Flashcards
what cells do leukocytozoon infect
erythrocytes
what transmits leukocytozoon and to what
blackflies transmit it to wild and domestic birds
locally, which birds are highly susceptible to leukocytozoon and which are resistant
domestic ducks susceptible and wild ducks, especially black ducks are resistant
what does leukocytozoon look like on a blood smear
the RBC nucleus is elongated and displaced to the side; females are blue and males are punk
when is transmission of leukocytozoon highest and in what population
spring; to ducklings shortly after they hatch
may get high mortality
for leukocytozoon, merogony occurs in ______________, gametogony occurs in ________________ and sporogony occurs in __________________
domestic ducks (in the liver and spleen); domestic ducks (in RBC); blackflies
what cells does haemoproteus infect and in what species
erythrocytes of wild and domestic birds, especially birds of prey in rescues
with haemoproteus, what stage in the host causes pathology and which is relatively benign
gametogony in the erythrocytes cause no damage but merogony in the endothelium, lung, liver, spleen, kidney causes problems
how can we differentiate haemoproteus from leukocytozoon on a blood smear
leukocytozoon displaces the nucleus of the RBC to the side but haemoproteus looks like purple granular material filling the RBC
what transmits haemoproteus and to what
midges and hippoboscid flies to wild and domestic birds (especially captive birds)
for haemoproteus, sporogony occurs in ___________, merogony occurs in ___________ and gametogony occurs in ______________
midges and hippoboscid flies; wild and domestic birds (endothelium, liver, spleen, lung, kidney); wild and domestic birds (RBC)
what is the name of the haemosporid apicomplexan parasites
Leukocytozoon and haemoproteus
some flagellates infect _________ and some infect _____________ (areas)
mucosal sites; blood
mucosal flagellate parasites generally _______________ and have ____________ life cycles
form cysts; direct
blood borne flagellate parasites generally infect hosts (how) and have __________ life cycles
using vectors; complex, multi-host
what are the 4 major groups of flagellate protists
diplomonads, trichomonads, amoeboflagellates, kinetoplastids
give examples of the following:
- diplomonads (2)
- trichomonads (1)
- amoeboflagellates (2)
- kinetoplastids (2)
- diplomonads: giardia, hexamita
- trichomonads: trichomonas
- ameoboflagellates: histomonas, dientamoeba
- kinetoplastids: trypanosoma, leishmania
what is the site of giardia infection
duodenum/upper small intestine
what is the structure of giardia
8 flagella, 2 nuclei prominent ventral disk
the giardia cyst is a rounded up ______________ with how many nuclei
what is a cyst synonymous with, if we were talking about apicomplexan parasites
trophozoite (2 squished together); 4 when mature
synonymous with an oocyst, we just call it a cyst now
how can you ID a giardia cyst
the contents shrink away from the cyst wall and it has 4 nuclei when mature
describe giardia life cycle
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
what is the main route of giardia infection
fecal-oral contamination with encysted forms
does giardia have a monoxenous or heteroxenous life cycle
monoxenous
what is the main clinical sign of giardia
malabsorptive enteritis with foul smelling, fatty diarrhea +/- blood
does cross-transmission of giardia between hosts occur
controversial
how can we diagnose giardia
fecal float; IFA; trophozoites seen in diarrhea if examined in saline directly; ELISA antigen tests
what is the primary treatment for giardia
metronidazole and fenbendazole; used to be a vaccine but no longer available due to limited effectiveness
where is trichomonas found in hosts?
GI, urogenital organs, crop of birds
how does trichomoniasis differ from giardia
no cysts formed -> direct transmission
what is the structure of giardia
3-5 flagella, 1 nucleus, undulating membrane
what is the life cycle of trichomoniasis
direct transmission of trophozoites -> divide by binary fission in the host
describe the pathogenesis of trichomonas in the following species:
1) cattle
2) pigs
3) horses
4) birds
cattle: venereal disease (vaginitis, early abortions)
pigs: non-pathogenic
horses: infects cecum and colon
birds: severe infections of crop and esophagus (also lower GI)
how do you diagnose trichomoniasis
- direct smears looking for trophozoites
- culture
what bird species is highly susceptible to oral trichomoniasis and why? what does it resemble? how can we differentiate?
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
what is the Histomonas meleagridis life cycle
divides by binary fission, no cyst, transmitted within Heterakis (cecal nematode eggs) as a paratenic host
how does histomonas work its way up the food chain
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
what is the life cycle of histomonas once ingested by the bird host
divide in the cecae -> trophozoites penetrate the mucosa -> enter blood -> go to liver -> rapid multiplication of trophozoites in the liver
what bird species is highly susceptible to Histomonas meleagridis
turkeys
what are the lesions of Histomonas meleagridis infection (2)
- edematous cecum
- yellow-green liver necrosis and lesions
what are the clinical signs of Histomonas meleagridis infection
droopiness, ruffled feathers, hanging wings
yellowish diarrhea
how do we treat Histomonas meleagridis
metronidazole, management, remove soil contact, anthelmentics to remove Heterakis host
what bird operations are most susceptible to Histomonas meleagridis infection and why
free-ranging due to soil contact and exposure to Heterakis (cecal nematode) which acts as the paratenic host
what is the appearance of ciliates
have cilia, usually arranged in rows
how do ciliates divide
binary fission; some genetic exchange by conjugation
T/F some ciliates form cysts
T
what are the two ciliate protists that cause disease in veterinary species
Balantidium coli and Ich multifiliis
Balantidium coli:
- where is it located
- does it form cysts? if yes, appearance
- replication
- mainly large bowel as a trophozoite
- yes; has a curved, dense nucleus, and thick cyst wall
- binary fission
what species does Balantidium coli infect? is it a zoonotic risk?
swine; yes (ingestion of cysts)
what are the clinical signs of Balantidium coli
how can we treat it
- diarrhea
- dysentery
- abdominal pain
- weight loss
Tetracyclines
Ich multifiliis host
- fish in aquaria
what is the life cycle of Ich multifiliis
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
what is the infective form of Ich multifiliis
tomites
where does microsporidia cause infection
GI tract or other MM
what is the structure of microsporidia
single-celled spore with a coiled filament (extrusive tube)
describe the microsporidia life cycle
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
