Protozoa-cats/dogs Flashcards
Protozoa prevalence
- Cystoisospora- most common;
- Sarcocystis- common in West, not BC
- Giardia
- Cryptosporidium
Mucosoflagellates
-direct life cycles
eg. Giardia, Tritrichonomas
-only asexual reproduction
Giardia
-oral transmission; water
-people only get zoonotic genotypes
-pets can have host specific and zoonotic genotypes
Taxonomy of giardia
- G. duodenalis- zoonotic
2.G. enterica - G. canis
- G. cati
Giardia Life cycle
1.Environment (cysts, survive for mths, immediately infective)
- Feces (millions of cysts)
- Host (trophozoites; attach to enterocytes, divide by binary fission)
PPP: 4-16days
Clinical signs of giardiasis
-often asymptomatic; can be acute, chronic, recurring
-diarrhea +/- mucous or fat, rarely fat
-flatulence
-vomiting
-nausea
-abdominal pain
-food allergies: dermatitis due to increased permeability of GIT wall
Diagnosis of giardia
**only test diarrheic animals or high risk households
- Fecal samples (3 samples over 2-3 day intervals)= smears
- Zinc sulfate flotation for cysts
- Immunofluorescent assays- cyst antigen from diagnostic lab
4.ELISA SNAP test= in clinic testing for cyst antigen
**genotyping difficult for vets. Just assume all giardia is zoonotic
Giardia appearence
Cyst= old man
Trophozoites: falling leaf motion. Can see flagella
Control of Giardia
-Only treat diarrheic animals or high risk houses
-Goal is to decrease clinical signs and environmental contamination. Likely won’t eliminate infection
-Inform clients of zoonotic risk
-Sanitation- bathe dog, disinfect environment (heat, dry, bleach)
-Drugs: metronidazole, fenbendazole, ronidazole
Epidemiology of pets with giardia
-Subclinical common
-Dogs: 7-40%
Cats: 8-10%
Risk factors:
-young animals
-suboptimal environment
-stressed/immunocompromised
-reinfection common
Tritrichomonas foetus
-cat strain: under 1yr, catteries, purebreds
-very long multiple flagella, nucleus visible
-shed and infective stage
-not environmentally resistant
-no cysts
Pathogenesis of Tritrichomonas foetus
-chronic large bowel diarrhea
Diagnosis of Tritrichomonas foetus
-culture and microscopy (InPouch TF)
>will appear more directional
-PCR
Treatment of Tritrichomonas foetus
No labeled treatment
Often self resolves
Can use Metronidazole, Ronidazole
Haemoflagellates
-Arthropod-transmitted
eg. Trypanosoma and Leishmania
-not in Canada unless imported with dogs
-indirect life cycle
Trypanosoma spp transmission
African: transmitted by tsetse flies
Others: transmitted by kissing bugs, tabanids, keds
Leishmania spp transmission
Transmitted by sand flies
Chagas Disease
-American Trypanosomiasis= Trypanosom cruzi
-Dogs from Texas, C and S America
Chagas disease appearance
Trypomastigotes in blood
Amastigotes in myocytes
Haemoflagellate (Trypanosoma cruzi) indirect life cycle
- Host
-asexual reproduction in cardiac and smooth muscle
*cardiomegaly in dogs; megaesophagus in humans - Arthropods take blood meal
- Arthropods (ex. kissing bugs)
-asexual reproduction in gut
-shed protozoa (trypomastigotes) in feces onto the host; host licks themselves
Coccidia
Direct life cycles=GIT
eg. Cystoisospora, Cryptosporidium
Indirect life cycles= Tissue cysts
eg. Toxoplasma
Coccidia host specificity
Coccidia is highly host specific, and GIT specific
Not zoonotic!
Common in shelters and young animals
Coccidia in dogs
Cystoisospora canis, ohioensis, burrowsi
Coccidia in cats
Cystoisospora felis, rivolta
Cystoisospora life cycle
PPP: 5-10days
1. Infection- eating paratenic host or eggs
2. Merogony- asexual reproduction; will burst out of GI epithelial cells
-Large pathogenesis
3. Gametogony- sexual reproduction; microgametocytes and macrogametocytes =microgametes burst out, form oocyst
4. Become unsporulated oocyst that exits in feces
5. 2-7 days sporogony period in environment
6. Sporulated oocyst: 4 sporozoites in 2 sporocysts
-ingested by paratenic host or DH
Cystoisospora oocysts
Unsporulated: very small
Sporulated: infective stage, resistant, 4 sporozoites in 2 sporocysts
Pathogenesis of coccidiosis
-Often asymptomatic; pups and kittens; stressed
-Heavily contaminated environment; Destroy epithelial cells in prepatent period before shedding
**diarrhea, dehydration, poor growth
-even in PPP
Diagnosis of coccidiosis
-clinical appearance
-fecal flotation (numbers of oocysts significant
Control of coccidiosis
-supportive
-environmental decontamination
-reduce shedding; treat dogs at weeks 3,5,7
-coccidiostatic drugs: sulfonamides, furazolidone
-coccidiocidal drugs: toltrazuril, ponazuril
Cryptosporidium
C. canis= dogs
C. felis = cats
C. parvum= people
C. muris= rarely people and pets
Cryptosporidium life cycle
Pathogenesis of cryptosporidium
-subclinical
-self limiting with secretory diarrhea (fluid loss in severe cases
-more issues in immunocompromised individuals (persistant infections usually denote an underlying issues eg. canine distemper
Diagnosis of cryptosporidium
-clinical appearance
-fecal flotation poor because so small
-fluorescent antibody tests/fecal antigen
Control of cryptosporidium
-Supportive= fluid therapy
-environmental decontamination
-Few drugs (Azithromycin, Tylosin, Paromycin)
Epidemiology of cryptosporidium
-hard to determine real prevalence
-self limiting: subclinical or secretory diarrhea
-most often human to animals zoonotic transmission
