Protozoa Flashcards
1
Q
The difference between giardia cysts and trophozoites
A
Cysts
- have 4 nuclei
- this is the infective stage
- found in solid feces
- small
- needs to be stained in order to be seen
Trophozoites
- tear shaped
- have 8 flagella
- found in loose feces
2
Q
Giardia lifecycle
A
- giardia are transmitted by ingesting the cyst stage in contaminated food or water. Can survive for months.
- excystation occurs in teh duodenum
- replication via longitudinal binary vision (asexual repro)
- Encystment occurs in the lower intestinal tract - infective cysts passed in feces
3
Q
Giardia duodenalis
Clinical signs
Giardia spp. Clinical signs
A
- usually none
Giardia spp. Clinical signs:
If any, they will have blunting of intestinal villi leading to malabsorption and diarrhea from damaged enterocytes
4
Q
Giardia duodenalis
Diagnosis
A
Fecal floatation - for cysts
- use zinc sulfate for detection
ELISA
5
Q
Giardia duodenalis
Treatment
A
- none approved
- fenbendazole and metronidazole used in dogs and cats
- treat once and everyone else in the household
6
Q
Giardia duodenalis
Control and zoonosis
A
Control
- bathe animals
- removal of feces
- difficult - resistant cysts
Zoonosis
Not sure if zoonotic, but treat it like it is
7
Q
Trichomonas blagburni
What animal gets it?
Characteristics
A
- cats
- pseudocysts
- longitudinal binary fission
8
Q
Feline trichomoniasis
Clinical signs
A
Large-bowel disease
- age of onset ~ 9 months
- chronic diarrhea (blood and/or mucus)
- tenesmus
- Flatulence
- irritated anus
- fecal incontinence: main complaint from clients
9
Q
Feline trichomoniasis
Transmission
A
- fecal-oral route
- survival outside host: needs nutrient rich substance to survive (diarrhea or water)
10
Q
Feline trichomoniasis
Diagnosis
A
- direct fecal smear (a fecal would kill it; also super temperature sensitive)
- culture
- PCR
- colonic biopsy
11
Q
Feline trichomoniasis
Treatment and control
A
No approved treatment
- ronidazole: watch for neuro signs as side effects though!
- metronidazole or tinidazole
- keep infected cats away from other cats
- no litter box sharing
12
Q
How to tell giardia trophozoites from tritchomonas trophozoites
A
Giardia move gracefully while tritrichomonas is spastic and unorganized
13
Q
Name 3 non-pathogenic trichomonads
A
- Pentatrichomonas hominis - found in cecum and colon of mammals
- Tritrichomonas canistomae and T. Felistomae - found in the mouths of dogs and cats
14
Q
Trypanosomes
- in what species are they found?
- how are they transmitted?
- what does it cause/
A
- found in blood and tissues of vertebrates
- transmitted by blood feeding arthropods (ie flies)
- mostly non pathogenic
15
Q
Trypanosoma cruzi
- what disease does it cause?
- who is the DH
- who are reservoir hosts
- what vector does it use
- where is it found
A
- causes American Trypanosomiasis in dogs and cats; causes Chagas disease in humans
- main DH: opossums and racoons
- reservoir hosts/spills over into dogs, cats and armadillos
- uses the reduviid bug (kissing bug) as a vector
- found in Mexico, central and south america; rare in the US
16
Q
Trypanosoma cruzi
Morphology
A
Uses a trypomastigote for the subterminal kinetoplast
Amastigote (pseudocyst)
17
Q
Trpanosoma cruzi
Lifecycle
A
- Metacyclic trypomastigotes are the infective stage; passed in feces of IH. Enter host via bite wound, scratch, etc.
- Trypomastigoes found in blood; enter cells of spleen, liver, lymphatics and muscle
- Amastigotes replicate via binary fission form clusters in pseudocysts
- Cells rupture and trypomastigotes remain in circulation or reinfect
- Transform into epimastigotes - replicate via binary fission
18
Q
American Trypanosomiasis: Dogs
(Trypanosoma cruzi)
Clinical signs
A
Acute stage: trypomastigotes in circulating blood
Chronic stage: no longer circulating
- congestive heart failure
- enlarged heart
- arrhythmia
- lethargy
- respiratory difficulties
- hepatomegaly
- anemia
19
Q
Trypanosoma cruzi
Diagnosis
A
Serological testing
- blood smear
20
Q
Trypanosoma cruzi
Treatment
A
- low efficacy against chronic disease
- harsh side effects
- treatment over 2 - 3 months: benznidazole, ravuconazole
21
Q
Cystoisospora and Eimeria spp (coccidia)
- in what species are they found
- geography
- how many hosts
A
- very species specifc ie stenoxenous
- worldwide
- monoxenous - parasitize one host (DH)
22
Q
Difference between cystoisopera and Eimeria eggs
A
Cystoisopera
- have 2 sporocysts and 4 sporozoites each
Eimeria
- have 4 sporocysts and 2 sporozoites each
23
Q
Name 4 cystoisopora found in dogs
A
C. Canis
C. Ohioensis
C. Burrowsi
C. Neorivolta
24
Q
Name 2 cystoisopora found in cats
A
- C. Felis
2. C. Rivolta
25
Cystoisopera
| Lifecycle
1. Undergo schizogony in feline small intestine
2. Undergoes gametogony (sexual reproduction) in epithelial cells of cat
3. Unsporulated oocyst then undergoes sporogony (asexual repro) to sporulated oocyst and makes it infective
26
Cystoisopora spp
| Clinical signs and pathogenicity
- occassional diarrhea and death
- enteritis, colitis, weight loss, dehydration
- not zoonotic (species specific)
27
Prevalence of canine coccidiosis
Younger animals will have highest incidence of infection
Older animals serve as carriers and reservoirs
28
Cystoisopora
| Control
- kennel sanitation; prompt feces removal
- disinfectants with high ammonia concentrations
- treatl all animals
- use steam or heat with disinfectants
29
Coccidosis treatment in dogs and cats
```
Sulfadimethoxine
Sulfaguanidine
Furazolidone
TMS
Sulfadimethoxine/ormetoprim
Quinacrine
Amprolium
Toltrazuril
Diclazuril
Ponazuril
```
30
Eimeria - is it a spurious parasite?
Yes; usually in dogs, sometimes in cats
Spurious = pseudoparasite.
When you see this its usually bc the dog ate another animal's poop
NOT A TRUE PARASITE OF THE DOG/CAT
31
Cryptosporidium spp.
| - seen in what animals? And in what location?
- C. Canis = dogs small intestine
- C. Felis = cats small intestine
- C. Parvum = small intestine of cows
Its species specific, have to get reinfected with same speceis for immunity to kick in
32
Cryptosporidium life cycle
1. Asexual reproduction in intestine of the host (schizogony0
2. Then the merozoites undergo gametogony
3. Oocysts are then passed in the feces or can reinfect the same host.
4. If oocysts are passed in the feces they will be ingested and tehn excyst sporozoites and start all over
33
Cryptosporidium spp.
| Transmission
- direct contact with infective oocyst in feces
- they are very hardy and spread very easily
- contaminated food, equipment, fomites, etc.
- water
- large number of oocysts excreted and require only a low infective dose
34
Cryptosporidium spp.
Oocyst resistance
What does not work?
1. Physical disinfection: heat, freezing, UV irridiation
2. Chemical disinfection: industrial strength chlorine and bleach, or hydrogen peroxide (let sit for 30 min)
Things that dont work: ethanol, isopropanol, lysol, formaldehyde, betadine, etc
35
Cryptosporidiosis
| Clinical signs
most infectious subclinical
- profuse, watery diarrhea (distinct smell)
- anorexia, dehydration, weight loss
- villous atrophy, enteritis
- healthy dogs/cat infections are usually self-limiting (get better on their own in 10 - 12 days)
- persistent infections denote underlying cause such as distemper
36
Cryptosporidiosis
| Diagnosis
can do a fecal float but they are very hard to see
- use an acid fast stain
- will see a ton of them at the top of your fluid
37
Cryptosporidiosis
| Treatment
- nitazoxanide: used for humans, kinda iffy
Drugs seen in literature:
- paromoycin
- tylosin
- azithromycin
38
Toxoplasmosis
- what is it caused by
- who is the DH
- IH?
- how is it transmitted
- Caused by toxoplasma gondii: an obligate, intracellular parasite
- DH = felidae family
- IH = most mammals
- transmission:
Acquired = ingesting infective oocysts, consumption of undercooked meat
Congenital = transplacental
39
Toxoplasma gondii
| Where are the various life stages found in the host?
- tachyzoites: rapidly dividing, found in liver, lungs, spleen, LN
- bradyzoites: slowly dividing, found in heart, skeletal muscle, eye, brain
- oocysts: found in feces of cat
40
Toxoplasma gondii
| Lifecycle
1. Cat ingests a sporulated oocyst, or a tachyzoite (transplacental), or a bradyzoite (from an IH). If the cycle starts with an IH, they contrac the parasite thru sporulated oocysts.
2. Parasite undergoes schizogony + gametogony in intestine or tachyzoites can migrate thru body of cat and infect anything except a RBC.
3. If parasite went to intestine, then they will develop oocysts that will pass in feces. If tachyzoite started migrating, then they could be transported thru placenta to fetus or host immunity can develop and they will develop into bradyzoites and develop as cysts in host tissue.
41
Toxoplasma gondii
| What is unique about the DH and IH of this parasite?
Cats are the DH, but they can act as both a DH and an IH because they can form bradyzoites and if something were to eat the cat, they would become infected.
42
Toxoplasma gondii
| When do oocysts sporulate? What effect does this have on human control of the parasite?
Once released in feces, they will sporulate every 1 - 5 days.
So if you clean the litter box every day, the oocysts will not be infective and you can eliminate exposure.
43
Toxoplasma gondii
| Name the 3 ways a DH can become infected
1. Ingesting sporulated oocysts
2. Ingesting tissue cyst (bradyzoite)
3. Tachyzoites (congenital - transplacentally)
44
Toxoplasma gondii
| How does shedding in cats work?
- no confirmed oocyst shedding in clinically ill cats.
- infected cats seroconvert 2 - 3 WEEKS after infection so by the time they are clinically ill, they have already shed their oocysts
- cats shed ONCE in their lifetime unltess they get reinfected
45
Toxoplasma gondii
| Describe disease in cats
- fever, anorexia, jaundice, hepatitis, pancreatitis, neuro problems, respiratory interference, death
46
Toxoplasma gondii
Diagnosis
Whats important to realize about some of these tests?
fecal exam
Biopsy
PCR
serological tests: IFA, ELISA
- important: one positive serum sample only indicates past infection!
- a 16-fold rise in titer in serum taken 2 - 4 weeks after 1st positive indicates acute aquired infection
47
Toxoplasma gondii
| Treatment in cats
- sulfonamide+pyrimethamine
- clindamycin hydrochloride
- TMS (trimethoprim-sulphonamide)
- supportive care
48
Toxoplasma gondii
Control
Zoonotic?
- do not feed raw meat
- keep cats indoors to prevent hunting
zoonotic!! Can cause neuro disease and birth defects, stillbirth
- cook meat thoroughly (can be found in pork)
- change litter box daily
- wear gloves when gardening
49
Neospora caninum
- DH?
- IH?
- geographic distribution
- transmission: aquired or congential?
- DH = dogs and coyotes
- IH = cattle, sheep, goats, deer, many mammals and birds
- world wide
- trasmission:
Acquired = ingesting oocysts, consumption of raw meat
Congenital = transplacental
50
Neospora caninum
name its 3 Lifestages and where they are found
When do oocysts sporulate?
1. Bradyzoite - found in CNS, can remain viable in dead tissue for 7 - 10 days
2. Tachyzoite - any tissue
3. Oocyst - sporulates within 24 hours
51
Neospora caninum
| Lifecycle
1. Dog ingests bradyzoites and it invades intestinal epithelium
2. Schizonts develop - schizogony occurs
3. Merozoites released - reinvade as 2nd schizont OR gamont develops
4. Gamonts undergo gametogony produce zygote which devlops into unsporulated oocyst which is passed in feces
5. Oocyst picked up by IH and sporulates to allow sporozoites to invade intestinal epithelium as tachyzoites
6. Tachyzoites encyst mainly in muscle, CNS or travel to placenta
52
Neospora caninum
| Describe disease in dogs
Most severe in congenitally infected puppies: they have limb paralysis with hind limb extenstion. But will only infect a couple pups in a litter; don't know why.
Will have generalized disease in some pups and older dogs. Will show CNS involvement, myocarditis, hepatitis and pneumonia.
Death if untreated.
53
Neopsora caninum
| Diagnosis
Just like toxoplasma
- fecal exam (oocysts)
- serological exam: IFA and ELISA (rise in titer in serum taken 2 - 4 weeks after 1st titer indicates acute acquired infection)
- biopsy
- PCR
54
Neospora caninum
| Treatment
- variable prognosis with treatment: better with adult dogs, nothing kills tissue cysts
- clinical improvement unlikely if rapidly ascending paralysis present
Adults/older puppies; TMS and pyrimethamine or clindamycin
Puppies 9 - 13 weeks: clindamycin
55
Neospora caninum
| Control
- limit oocyst contamination food/water
- remove dead animals or aborted fetuses
- do not breed bitches infected with N. Caninum
- do not breed pups from infected bitches
- do not feed raw meat
56
Hammondia spp.
- phylum
- what other parasite does it look like? What is the difference?
- what type of lifecycle does it have?
- how is it transmitted?
- Apicomplexa
- looks JUST like neospora and toxoplasma but Hammondia is not really pathogenic
- it has an obligatory 2 host lifecycle
- transmitted to DH via ingested bradyzoites and transmited to IH via ingested oocysts
57
Hammondia hammondi
DH?
IH?
Is it pathogenic?
```
DH = cats
IH = rordents, pigs, dogs
```
Non-pathogenic!
58
Hammondia heydorni
DH?
IH?
Pathogenic?
```
DH = dogs, coytoes
IH = catle, buffalo, sheep, moose, goats, dogs
```
It may cause diarrhea
59
Hammondia spp
| Lifecycle
- no congenital transmission
DH: ingest bradyzoites
- schizogony and gametogony in intestine
- oocysts sporulate outside DH
- no extraintestinal stages = no tachyzoites, no cysts
IH: ingest oocysts
- tachyzoites and bradyzoite cysts in skeletal muscle, lungs, LN, occasionally brain
60
Hammondia spp.
| Diagnosis
- looks JUST like neospora and toxoplasma
- fecal floatation
- serology for neopora or toxoplasma
- experimental PCR
61
```
Sarcocystis spp
Phylum?
DH?
IH?
Geography?
Transmission?
```
- apicomplexa
- DH: carnivore
- IH: herbivore
- worldwide
- transmission: predator-prey relationship
DH = consuming IH containing sarcocysts
IH = ingesting food contaminated with sporocysts
62
Sarcocystis spp.
| Lifecycle
1. Gametogony occurs in the intestine of the DH
2. Sporocysts released in feces
3. Schizonts form in cells of IH and will burst releasing sarcocysts in skeletal and cardiac muscle of IH.
63
Sarcosporidiosis
| Diagnosis and control
- fecal float (sporulated sporocysts) DH
- biopsy
- western blot (Ab in serum or CSF)
- PCR
- history
Control
- bury/incarcerate dead livestock
- cover stored grain
- keep carnivores out of animal housing facilities
64
Cytauxzoon felis
- phylum? What thingy under phylum is it? Not a coccidia...
- DH?
- IH? Vector?
- reservoir host?
- geography
- apicomplexa. Its a piroplasm; a protozoan parasite
- DH = domestic cats
- IH/vector = ticks: dermacentor variabilis and Ambylyomma americanum
- reservoir host = bobcats
- geography: emerging disease in N. America
65
Cytauxzoon felis
| Epidemiology: where is it found? What season?
- usually found in feral cats (access to more ticks)
| - most often seen in the summer
66
Cytauxzoon felis
| Life cycle
1. Tick feeds on infected host and ingests the piroplasm (infective stage) in RBCs
2. Asexual development - merozoites migrate to salivary glands of tick
3. Infected tick feeds on DH (cat). Merozoites enter macrophage, schizogony occurs in macrophages. Merozoites released when macrophage ruptures and enters RBCs where they develop into piroplasms.
67
Cytauxzoon felis
| What type of Transmission can occur
Transstadial transmission can occur. = tick can pick it up at any life stage and will pass with it as it molts and develops
68
Cytauxzoon felis
| Pathogenicity: 2 forms
Fatal form:
- fever, depression, lethargy, anorexia, jaundice, death
Non-fatal form:
- similar signs as fatal form but may also be asymptomatic and have persistent parasitemia
69
Cytauxzoon felis
| Which phase is most destructive?
Schizogenous phase most destructive
| When macrophages are infected with schizonts and block blood vessels
70
Cytauxzoon felis
| Diagnosis and control
Giemsa stained blood smears
PCR
Biopsy
Control: keep cats indoors, tick control, promptly remove ticks
71
Cytauzxoon felis
| Treatment
Supportive care
Atovaquone and azithromycin
Heparin as needed
72
Babesia spp.
Phylum - what thingy under phylum?
Geography
DH?
- apicomplexa: invasive stage = piroplasm
- worldwide
- DH = dogs
73
Babesia
| Lifecycle
1. On RBC of dog, piroplasms divide by binary fission.
2. Piroplasm (infective stages) ingested when tick ingests RBCs
3. Undergoes schizogony in larval tick.
4. Experiences transstadial transmission where schizont stays with tick as it molts and undergoes 2nd generation schizogony
5. Then undergoes gamogony to develop into a motile zygote and moves to salivary glands of the tick.
6. Motile zygote undergoes sporogony and develops to sporulated oocyst.
7. Sporozoites released and enter vertebrate host during blood meal.
74
What forms of transmission can Babesia spp. Undergo?
Both transstadial and transovarial transmission:
Transstadial = motile zygote moves to salivary glands
Transovarial = motile zygote enters ovary of adult female, enters developing egg and moves into salivary glands of developing tick larva
75
Name 2 species of Babesia and their vertebrate host and associated vector:
Babesia canis
- vertebrate host: dogs, wolves, jackels
- arthropod host: ixodid ticks = rhipicephalus sanguineus or dermacentor spp.
Babesia gibsoni
- vertebrate host: canids
- arthropod host: suspect rhipicephalus sanguineus in US
76
Babesia canis
Who usually carries it?
Who exhibits clinical signs?
How is it transmitted?
- adult dogs are usually the carriers with unapparent disease
- puppies experience severe disease
- transmitted via ticks
77
Babesia gibsoni
- who usually experiences disease?
- where did it come from?
- how is it transmitted?
- adults and puppies get same disease, at any age
- introduced in US in 70s -80s; endemic in Africa, Middle east, Asia
- transmitted in US via fighting, ear cropping, tail docking, blood transfusions and transplacentally
78
Babesia spp.
| Clinical signs
Anemia, pale mm, fever, amber/brown urine, splenomegaly, thrombocytopenia
79
Babesia spp
| Diagnosis
- blood film: piroplasms only visible if clinically ill.
- IFA: not good; lots of false negatives/positives, titers >1:80 significant
- PCR: will detect carriers, differentiate between species
80
Babesia canis and Babesia gibsoni
| Treatment
Babesia canis
- no therapy required
- relapse possible
- imidocarb dipropionate (imizol)
Babesia gibsoni
- azithromycin and atovaquone (combo treatment)
- supportive care
- relapse more likely
- does not respond well to imidocarb dipropionate
81
Giardia spp.
Hosts
Geographics
Lifecycle type - indirect or direct
- hosts: mammals, birds, amphibians
- world wide
- direct
