25: SA Protozoa

How do flagellate protozoa replicate

Binary fission (asexually)

How do some flagellate protozoa survive in the environment

Some form cysts

Feline GIT protozoa

Tritrichomonas blagburni

Where does Tritrichomonas blagburni set up shop

Terminal GIT on the surface of epithelial cells

Tritrichomonas blagburni life cycle

Direct

How does Tritrichomonas blagburni exist in the environment

It doesn’t really. It can form pseudocysts, but they are not effective

Primary route of Tritrichomonas blagburni transmission

Co-grooming (fecal-oral)

Tritrichomonas blagburni structure

3 anterior flagella and 1 posterior flagellum

Patient demographic for Tritrichomonas blagburni

Cats <2 years old

Clinical sign associated with Tritrichomonas blagburni

Chronic large bowel diarrhea (weeks to years!)

Diagnostics for Tritrichomonas blagburni

Direct smear or PCR

How do we make our PCR more sensitive

Culture the fecal sample before doing a PCR

Best treatment for Tritrichomonas blagburni

Ronidazole q24 hours for 14 days

Realistically accessible treatment for Tritrichomonas blagburni

Metronidazole + fenbendazole + enrofloxacin for several days

Consideration when treating Tritrichomonas blagburni

Quarantine the infected cats!

T/F: Tritrichomonas blagburni is zoonotic

False

Route of trypanosome transmission

Stercorarian transmission: organism is ingested by the kissing bug and passed out in the kissing bug feces

SA trypanosome of the western hemisphere

Trypanosoma cruzi

Stage that is infectious to the kissing bug (and where is it)

Trypomastigote in the blood stream

Stage that is infectious to the IH (and where is it)

Infective trypomastigote in the kissing bug feces

Stage that is replicating in the IH (and where is it)

Amastigote inside the host cells

How does Trypanosoma cruzi cause disease in the IH

Asexual replication in the cells causes cellular damage

Routes of Trypanosoma cruzi infection

• Kissing bug feces

• Ingestion of the kissing bug

• Ingestion of other hosts

• Transplacental and transmammary

• Blood transfusions

Syndrome associated with Trypanosoma cruzi

Usually asymptomatic, but if symptomatic causes cardiopulmonary disease

Phases of CS associated with Trypanosoma cruzi

Acute → latent → chronic

CS associated with acute (<30 days) phase of Trypanosoma cruzi

• Cardiac and respiratory inflammation

• Fatal arrhythmias

• Fatal myocarditis

CS associated with latent phase of Trypanosoma cruzi

None

CS associated with chronic phase of Trypanosoma cruzi

• Heart enlargement

• Conduction deficits

• Heart failure → death

Patient demographic that has a poorer prognosis if infected with Trypanosoma cruzi

Patients that are young when we diagnose the cardiac disease

Diagnostics used for Trypanosoma cruzi

• History of travel to endemic areas (the south)

• Blood smear

• PCR

• ± Biopsy

Indirect diagnostics for Trypanosoma cruzi

• Ab testing (in other countries)

• Radiographs

• Echo/ECG

Labeled treatment for Trypanosoma cruzi

None approved

Best treatment for Trypanosoma cruzi

Itraconazole and amiodarone

T/F: Trypanosoma cruzi is zoonotic

True → Chaga’s disease!!!

“Subtypes” of giardia that are of most veterinary importance

• Dog: C and D

• Cat: F

Giardia life cycle

Direct

Giardia transmission

Fecal oral

Form of Giardia shed by host

Trophozoite or cyst

Evolutionary benefit of Giardia cysts

Survives better in environment and water

When do we find Giardia trophozoites v cysts

Trophozoites more commonly seen in diarrhea, cysts more in formed feces

Giardia trophozoite morphology

Squished and clear with 8 flagella

Giardia cyst morphology

Clear spheres, may be able to see nuclei and axonemes

Giardia PPP

5-7 days

When should we retest when treating Giardia

2 days after conclusion of treatment

CS associated with Giardia

Mucoid diarrhea

When is Giardia bad

If patient gets dehydrated and has severe GIT irritation

How does Giardia cause clinical disease

Thought maybe to do with inhibition of brush border enzymes, can also cause villous atrophy and crypt hyperplasia

Diagnostics for Giardia

• Direct smear

• Zinc fecal float

• Ag testing

What is detected by Giardia Ag tests

Cyst wall proteins

Labeled treatment for Giardia

Metronidazole (Ayradia)

Best treatment for Giardia

Fenbendazole ± metronidazole

Treatment length for Giardia

At least 5 days in a row