Protozoa

What is a trophozoite?

The motile (moving), active form of a protozoan

What is an oocyst?

A fertilized egg stage shed in feces

What is a sporozoite?

The motile, infective form of a protozoan

What is a flagellum?

A long, whip-like appendage used for movement

What defines flagellates?

Protozoa that possess at least one flagellum in their trophozoite form

How do flagellates move?

Using flagella

Where do flagellates typically live in the host?

In liquid portions like blood and bodily fluids

What shape are flagellates often?

Pear or bullet shaped

How do amoebae move?

Using pseudopodia (false feet)

What are the two forms of amoebae?

Trophozoite and resistant cyst

What is the trophozoite form of amoebae?

Motile, active form in liquid

What is the cyst form of amoebae?

Inactive, resistant form in the environment

What shape are amoebae?

Amorphous (blob-like, poorly defined)

What are ciliates covered in?

Cilia (tiny, short hairs)

How do ciliates move?

Using cilia

What are the two forms of ciliates?

Motile trophozoite and resistant cyst

How does the ciliate trophozoite move?

Darting and twirling in liquid using cilia

What is unique about Apicomplexa?

They are the most diverse and complex protozoa

What species and apicomplexa infect

Everyone

How do Apicomplexa move?

Minimal movement using internal organelles and undulations

What shape are Apicomplexa?

Banana or boomerang shaped

What type of protozoa is Giardia?

Flagellate

Where does Giardia live in the host?

Small intestine

Which animals can Giardia infect?

Dogs, cats, ruminants, pigs, horses, and primates

What are clinical signs of Giardia in young animals?

Soft stools, diarrhea, possibly chronic, fatty/mucoid stools

What are clinical signs of Giardia in adults?

Usually asymptomatic

Does Giardia have zoonotic potential?

Yes (Assemblage A affects humans, dogs, cats)

What is the prepatent period (PPP) for Giardia?

About 1 week

What diagnostic forms of Giardia exist?

Trophozoite and cyst

How is Giardia transmitted?

Ingestion of cysts in contaminated food or water

What happens during excystation in Giardia?

Cysts release two trophozoites

How does Giardia reproduce?

Longitudinal binary fission

Where does encystation occur in Giardia?

As trophozoites move toward the colon

What forms of Giardia can be found in stool?

Both cysts and trophozoites

What is the gold standard test for Giardia?

Direct Fluorescent Antibody (DFA)

What test is highly sensitive and specific for Giardia?

PCR

What test is fast and convenient for Giardia?

ELISA

Why are multiple Giardia samples often needed?

Intermittent Shedding

What is the best testing approach for Giardia?

Combination testing

What is another name for Tritrichomonas foetus?

Trich

What type of of protozoa is Tritrichomonas?

Flagellate

How many flagella does Tritrichomonas foetus have?

Three anterior, one posterior

How does Tritrichomonas foetus move?

Rolling with abrupt directional changes

What environmental conditions kill Tritrichomonas foetus?

High heat and drying

How many life stages does Tritrichomonas foetus have?

One trophozoite stage

How is Tritrichomonas foetus transmitted in cattle?

Direct contact during mating

What are clinical signs in bulls infected with Tritrichomonas foetus?

None (asymptomatic)

What are clinical signs in cows with Tritrichomonas foetus?

Infertility, early embryonic death, pyometra, endometritis (abortions not common)

How is Tritrichomonas foetus diagnosed in bulls?

Culture of preputial scrape

What is the treatment for Tritrichomonas foetus in cattle?

Cull infected bulls

Are there effective drugs for Tritrichomonas foetus in cattle?

No safe, effective treatment

How is metronidazole involved with Tritrichomonas foetus?

Metronidazole is not approved for use (even off label) in food animals ever.

Are vaccines effective for Tritrichomonas foetus?

No

What is feline tritrichomonosis?

Infection of cats with Tritrichomonas foetus

Which cats are most susceptible to feline tritrichomonosis?

Cats under 1 year

What condition does feline tritrichomonosis cause?

Colitis

What are signs of feline tritrichomonosis?

Chronic diarrhea with blood and mucus

How is feline tritrichomonosis transmitted?

Fecal-oral route

Where is feline tritrichomonosis most common?

Shelters and catteries

How is feline tritrichomonosis diagnosed?

Rectal swabs and fecal culture

What type of protozoa is Toxoplasma gondii?

Apicomplexa (coccidia)

What diagnostic test is common for Toxoplasma in cats?

Fecal flotation

What other tests detect Toxoplasma?

Blood or serum tests

What symptoms are associated with toxoplasma?

Usually asymptomatic

When do Toxoplasma infections show symptoms?

In immunocompromised hosts or tissue infections

Which system is most likely affected by Toxoplasma?

Central nervous system

Can Toxoplasma cause abortion?

Yes

What are signs of Toxoplasma in cats?

Fever, weight loss, lethargy

What can congenital Toxoplasma infection cause?

Neurologic disease, birth defects, stillbirth

What type of protozoa is Cryptosporidium?

Apicomplexa (coccidia)

Is Cryptosporidium zoonotic?

Yes

What is the infective stage of Cryptosporidium?

Oocyst

What is the treatment for Cryptosporidium?

There is no specific treatment, mostly just supportive care

How is Cryptosporidium transmitted?

Fecally contaminated water or food

What happens after ingestion of Cryptosporidium oocysts?

Release of sporozoites that infect epithelial cells

What is a unique feature of Cryptosporidium lifecycle?

Auto-reinfection happens via thin-walled oocysts

What are clinical signs of Cryptosporidium?

Profuse watery diarrhea, abdominal pain

Why is Cryptosporidium hard to detect on fecal flotation?

Oocysts are VERY small

What stain is used for Cryptosporidium on smear?

Acid-fast stain

What type of protozoa is Babesia canis?

Apicomplexa (hemoprotozoa)

What is the definitive host of Babesia canis?

Dog

What is the intermediate host of Babesia canis?

Tick

How long must a tick attach to transmit Babesia?

24-48 hours

Where is Babesia most common geographically?

Southern regions with high tick prevalence.

How is Babesia diagnosed?

Blood smear or PCR

Where is Babesia found in the host?

Inside red blood cells

What shape is Babesia?

Pear-shaped

How does Babesia infect dogs?

Tick releases sporozoites into bloodstream

What happens to RBCs infected with Babesia?

They rupture, releasing protozoa into the bloodstream.

What are symptoms of Babesia infection?

Hemolytic anemia, fever, anorexia, pallor

What is the treatment for Babesia?

Imidocarb dipropionate (anti-protozoal), doxycycline, metronidazole

Does treatment eliminate Babesia completely?

No, dogs remain carriers forever

How can Babesia be prevented?

Tick control/preventatives