Parasitology Trichomonads and Giardia Flashcards
Subphylum Mastigophora
Have flagella all or part of life cycle
Move by flagella
Divide by longitudinal binary fission
Mucosal flagellates live in mucosa or lumen (transmitted by contact or cysts)
Blood/tissue flagellates live in blood or tissue (transmitted by insect vectors)
Order Trichomonadida
aka Trichomonads
Usually nonpathogenic- commensals
Normally luminal parasites- may be present in diarrheic feces but not the cause
Divide by longitudinal binary fission
No true cyst stage
Transmitted by direct contact or fecal-oral
Tritrichomonas foetus
Venereal disease of cattle
Bulls are asymptomatic carriers
Infertility, early embryonic death, EARLY ABORTION, and pyometra
Diagnosis of Tritrichomonas foetus in cattle
Sample bulls b/c they are carriers- rest 1-2 weeks prior to sampling so protozoa numbers increase
Preputal scrapping and culture (in-pouch system)
If cows are sampled, obtain from anterior vagina or cervical os
Prevention and treatment of Tritrichomonas foetus in cattle
AI
Cull infected bulls and replace with negative young bulls
Cull open cows or rest for 4 months (she will clear it)
Use virgin or pregnant replacements
There is no good treatment b/c it is illegal to use metronidazole in food animals
Tritrichomonas foetus in cats
Chronic, waxing and waning large bowel diarrhea
Diarrhea is often of cow-pie consistency, malodorus, and occasionally contains mucus or fresh blood
Involuntary fecal dribbling and inflammation of the anus
Is hard to diagnose
Diagnosis of Tritrichomonas foetus in cats
Demonstrate trophozoites in feces (jerky movements), don’t confuse with Giardia (move like falling leaf)
Use fresh fecal material b/c trophoziotes degenerate quickly outside of host- flotation doesn’t work, fecal smear does
Also have in-pouch
PCR
Treatment of Tritrichomonas foetus in cats
Use ronidazole (same class as metro) but it may actually prolong diarrhea
Treated and non-treated cats will usually resolve diarrhea within 2 years
Many treated cats still positive
Tritrichomonas foetus cats and cattle
Cat strains will infect cattle but less pathogenic for cows than the cattle strains
Cattle strains will infect cats
Pathogenicity for it in cats still being examined
Trichomonas gallinae
Infects the crop, oronasal cavities and esophagus in birds
A problem in pigeons and song birds
Can’t eat as well
Can be associated with bird feeders
Life cycle of Giardia (duodenalis)
Cysts are ingested in water or in contaminated materials from the environment
The cysts excyst and trophozoites develop in small intestine
Become cyst again when they will be moved
Clinical signs of Giardia duodenalis
Diarrhea usually doesn’t contain blood, is often fatty
Diarrhea can be intermittent
Malabsorption diarrhea
Signs develop about 1 week after infection- if they develop
Diagnosis of Giardia
Demonstrate trophozoites/cysts in smears or cysts in fecal flotations (Zinc-sulfate soln b/c similar specific gravity as cysts; stain with iodine stain as well) Cysts are shed intermittently so must examine 3 samples taken over a 1 week period Immunodetection methods (IDEXX snap test- detects the cyst wall protein)
Assemblage A
Humans, dogs, beavers, livestock
Assemblage B
humans, dogs, beavers
