Protozoa-cats/dogs

Question 1

Protozoa prevalence

Answer 1

1. Cystoisospora- most common;
2. Sarcocystis- common in West, not BC
3. Giardia
4. Cryptosporidium

Question 2

Mucosoflagellates

Answer 2

-direct life cycles
eg. Giardia, Tritrichonomas

-only asexual reproduction

Question 3

Giardia

Answer 3

-oral transmission; water
-people only get zoonotic genotypes
-pets can have host specific and zoonotic genotypes

Question 4

Taxonomy of giardia

Answer 4

1. G. duodenalis- zoonotic
   2.G. enterica
2. G. canis
3. G. cati

Question 5

Giardia Life cycle

Answer 5

1.Environment (cysts, survive for mths, immediately infective)

2. Feces (millions of cysts)
3. Host (trophozoites; attach to enterocytes, divide by binary fission)

PPP: 4-16days

Question 6

Clinical signs of giardiasis

Answer 6

-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

Question 7

Diagnosis of giardia

Answer 7

**only test diarrheic animals or high risk households

1. Fecal samples (3 samples over 2-3 day intervals)= smears
2. Zinc sulfate flotation for cysts
3. 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

Question 8

Giardia appearence

Answer 8

Cyst= old man

Trophozoites: falling leaf motion. Can see flagella

Question 9

Control of Giardia

Answer 9

-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

Question 10

Epidemiology of pets with giardia

Answer 10

-Subclinical common
-Dogs: 7-40%
Cats: 8-10%

Risk factors:
-young animals
-suboptimal environment
-stressed/immunocompromised
-reinfection common

Question 11

Tritrichomonas foetus

Answer 11

-cat strain: under 1yr, catteries, purebreds
-very long multiple flagella, nucleus visible
-shed and infective stage
-not environmentally resistant
-no cysts

Question 12

Pathogenesis of Tritrichomonas foetus

Answer 12

-chronic large bowel diarrhea

Question 13

Diagnosis of Tritrichomonas foetus

Answer 13

-culture and microscopy (InPouch TF)
>will appear more directional
-PCR

Question 14

Treatment of Tritrichomonas foetus

Answer 14

No labeled treatment
Often self resolves

Can use Metronidazole, Ronidazole

Question 15

Haemoflagellates

Answer 15

-Arthropod-transmitted
eg. Trypanosoma and Leishmania

-not in Canada unless imported with dogs

-indirect life cycle

Question 16

Trypanosoma spp transmission

Answer 16

African: transmitted by tsetse flies

Others: transmitted by kissing bugs, tabanids, keds

Question 17

Leishmania spp transmission

Answer 17

Transmitted by sand flies

Question 18

Chagas Disease

Answer 18

-American Trypanosomiasis= Trypanosom cruzi

-Dogs from Texas, C and S America

Question 19

Chagas disease appearance

Answer 19

Trypomastigotes in blood

Amastigotes in myocytes

Question 20

Haemoflagellate (Trypanosoma cruzi) indirect life cycle

Answer 20

1. Host
   -asexual reproduction in cardiac and smooth muscle
   *cardiomegaly in dogs; megaesophagus in humans
2. Arthropods take blood meal
3. Arthropods (ex. kissing bugs)
   -asexual reproduction in gut
   -shed protozoa (trypomastigotes) in feces onto the host; host licks themselves

Question 21

Coccidia

Answer 21

Direct life cycles=GIT
eg. Cystoisospora, Cryptosporidium

Indirect life cycles= Tissue cysts
eg. Toxoplasma

Question 22

Coccidia host specificity

Answer 22

Coccidia is highly host specific, and GIT specific

Not zoonotic!

Common in shelters and young animals

Question 23

Coccidia in dogs

Answer 23

Cystoisospora canis, ohioensis, burrowsi

Question 24

Coccidia in cats

Answer 24

Cystoisospora felis, rivolta

Question 25

Cystoisospora life cycle

Answer 25

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

Question 26

Cystoisospora oocysts

Answer 26

Unsporulated: very small

Sporulated: infective stage, resistant, 4 sporozoites in 2 sporocysts

Question 27

Pathogenesis of coccidiosis

Answer 27

-Often asymptomatic; pups and kittens; stressed
-Heavily contaminated environment; Destroy epithelial cells in prepatent period before shedding

**diarrhea, dehydration, poor growth
-even in PPP

Question 28

Diagnosis of coccidiosis

Answer 28

-clinical appearance
-fecal flotation (numbers of oocysts significant

Question 29

Control of coccidiosis

Answer 29

-supportive
-environmental decontamination
-reduce shedding; treat dogs at weeks 3,5,7
-coccidiostatic drugs: sulfonamides, furazolidone
-coccidiocidal drugs: toltrazuril, ponazuril

Question 30

Cryptosporidium

Answer 30

C. canis= dogs

C. felis = cats

C. parvum= people

C. muris= rarely people and pets

Question 31

Cryptosporidium life cycle

Question 32

Pathogenesis of cryptosporidium

Answer 32

-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

Question 33

Diagnosis of cryptosporidium

Answer 33

-clinical appearance
-fecal flotation poor because so small
-fluorescent antibody tests/fecal antigen

Question 34

Control of cryptosporidium

Answer 34

-Supportive= fluid therapy
-environmental decontamination
-Few drugs (Azithromycin, Tylosin, Paromycin)

Question 35

Epidemiology of cryptosporidium

Answer 35

-hard to determine real prevalence

-self limiting: subclinical or secretory diarrhea
-most often human to animals zoonotic transmission