Feline trichomonosis Flashcards
What are Trichomonads
Trichomonads are protozoa residing as parasites or commensals of animals
They live in mucous membrane-lined, anaerobic to microaerophilic, non-sterile organ cavities such as the gastrointestinal and reproductive tracts
Where does feline T. foetus sits in the GI tract
Feline T. foetus colonize the distal ileum and colon resulting in lymphoplasmacytic and neutrophilic colitis and foul smelling diarrhea
What are the key epidemiological features
Trichomonosis is presumed to be transmitted from cat to cat via the fecal-oral route
- trichomonads do not form cysts and therefore do not persist for more than a few hours under clean, dry and aerobic conditions
Cats with diarrhea and concurrent trichomonosis are generally young (median age, 1 year)
Cats from catteries or shelters appear to be at increased risk
What is the clinical presentation of feline tritrichomonas
Feline trichomonosis is characterized by a waxing and waning large bowel diarrhea
- owners often report that their cat has had diarrhea since adoption
- frequency of bowel movements ranges from once to eight times a day
- the feces often contains mucus and/or fresh blood +/- straining
- diarrhea is typically semi-formed to “cow pie” in consistency and malodorous
In most cases infected cats maintain good health, and a normal appetite and body condition, which presumably reflects confinement of the infection to the colon
Some kittens will develop fecal incontinence, and overt swelling and inflammation of the anal region from fecal scalding
What is the effect of antibiotherapy on cats suffering trichomonosis
A common feature of Tritrichomonas species diarrhea is that during administration of antimicrobial drugs fecal consistency improves and trichomonads are difficult to detect, but diarrhea containing trichomonads reappears shortly after treatment is discontinued
What are the patomechanisms explaining diarrhea
Pathogenic factors associated with trichomonosis include interaction with endogenous bacterial flora, adherence to host mucus and epithelium, and elaboration of cytotoxins and enzymes
- in naturally infected cats, Tritrichomonas species reside within the superficial mucus and in contact with the surface epithelium of the cecum and colon
What are the different means to diagnose feline trichomonosis and what are their advantages and inconvenients
Direct fecal wet mount examination
- techincal considerations:
- feces must be fresh and diarrheic
- advantages:
- affordable
- inconvenients:
- sensitivity is low (<14%)
- difficult to differentiate Tritrichomonas from Giardias
Fecal culture (InPouch TF)
- technical considerations:
- needs to be performed in-house
- advantages:
- non-expensive
- sensitivity around 55%
- inconvenients:
- does not differentiate Tritrichomonas from Pentatrichomonas hominis
PCR
- technical considerations:
- can detect both live and dead organisms
- advantages:
- most sensitive
- inconvenients:
- expensive
- false-negative results possible
How to collect the best fecal sample
Select only fresh and diarrheic feces for diagnostic testing
Any oral antimicrobial agents should be withdrawn for a minimum of several days prior to fecal collection
Collect feces using the colon flush technique (+++), using a fecal loop inserted per rectum (++), or immediately after voiding without contaminating litter (+)
Do not refrigerate feces intended for wet mount examination or culture, as this will kill the trichomonads
Collect the recommended amount of feces for optimal test results
How is feline trichomonosis treated
Ronidazole, a nitroimidazole similar to metronidazole, is the only antimicrobial with a convincing efficacy for treatment of feline Tritrichomonas species infection
A dose of 30 mg/kg, PO, q24h for 14 days is likely to be most effective in resolving diarrhea and eradicating Tritrichomonas species infection
What are the signs of ronidazole toxicity
Ronidazole has potential neurotoxic effects including lethargy, inappetence, ataxia and seizures
Side effects generally resolve if the drug is withdrawn immediately
Do not reinstitute or repeat treatment if signs of toxicity occur
Which cats should not be treated with ronidazole
Cats with systemic illnesses that could confound recognition of adverse drug effects
Pregnant or nursing queens
Kittens under 12 weeks
Cats with former side effects with ronidazole
How would you interpret/manage a cat still infected with trichomonosis after a treatment with ronidazole
If Tritrichomonas species infection is confirmed following treatment with ronidazole, three possibilities need to be considered:
- underdosing: insufficient dose or duration of ronidazole
- reinfection by another cat in the household that may or may not be showing clinical signs of diarrhea
- if other causes of treatment failure can be ruled out, persistent infection can likely be attributed to infection by a strain of Tritrichomonas species that is resistant to ronidazole
