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226 Cryptosporidiosis

Cystoisospora spp, Tritrichomonas foetus, occur) and are recommended only for oocyst • Another fecal analysis may be required if diar-
molecular typing.
Toxoplasma gondii, Entamoeba histolytica • Intestinal biopsy may not confirm infection • Animals with chronic infection should be
rhea persists and/or recurs after treatment.
VetBooks.ir inflammatory bowel disease, GI lymphoma, and is not cost effective. Necropsy samples re-evaluated at frequent intervals to assess
• Other causes of diarrhea and weight loss:
progress.
hyperthyroidism, others (p. 1213)
should be taken within hours after death
Initial Database because postmortem autolysis can prevent PROGNOSIS & OUTCOME
confirmation.
• Complete fecal examination consisting of
direct smear, Sheather’s solution flotation, TREATMENT Prognosis is good with treatment in cats that
and ZnSO 4 analysis is recommended for cats do not have FeLV/FIV infection. Prognosis is
with diarrhea. Treatment Overview guarded with protein-losing enteropathy and
○ Cryptosporidium oocysts are small but The overall goals of treatment are to cure the weight loss.
may be identified by light microscopy at infection, resolve clinical signs, and prevent
100× power using any of these techniques. further oocyst shedding. High numbers of PEARLS & CONSIDERATIONS
False-negative results are common. oocysts may still be shed after completion of
○ Multiple fecal samplings improve the a course of therapy with resolution of clinical Comments
likelihood of finding oocysts. signs. Treatment should persist in an attempt • This disease occurs predominantly in
○ Phase microscopy on unstained prepara- to stop fecal shedding of oocysts. immunocompromised cats.
tions from a Sheather’s fecal float may offer • Disease has also been reported in young
a greater chance of finding the oocyst but Acute General Treatment puppies secondary to immunocompromise
still may yield negative results. • Parenteral fluid therapy to correct hypovo- from other diseases.
○ Microscopic identification of oocysts may lemia, electrolyte imbalances, and acid-base • Glucocorticoids and other immunosuppres-
require submission of feces to a commercial disturbances if present sive agents should be avoided until infection
laboratory for acid-fast staining (modified • Antiprotozoal and antibiotic agents are is resolved.
Ziehl-Neelsen or Kinyoun technique) effective.
or antigen detection by immunologic ○ Azithromycin 7-15 mg/kg PO q 12h Prevention
methods (direct immunofluorescence for 5-7 days, current drug of choice for • This is a disease that is prevalent in over-
assay [DFA]), enzyme immunoassay human cryptosporidiosis. Studies in cats crowded and unsanitary conditions, and
[EIA]). have not been performed, but efficacy reducing environmental contamination with
○ Use of multiple methods of testing during would be expected. improved sanitation is an important aspect
clinical disease is recommended. ○ Paromomycin 125-165 mg/kg PO q of prevention.
• CBC, serum biochemistry profile, urinalysis, 12h for 5 days was the traditional drug • Although 5% ammonia will kill parasites, it
total T 4 , abdominal imaging: if diarrhea of choice, but because of side effects, has requires 18 hours of contact for effect. Higher
and weight loss are present (rule out other fallen from favor concentrations of ammonia are required if
disorders) ○ Tylosin 11 mg/kg PO q 12h for 28 days, contact time is shortened. Cryptosporidium
• FeLV and FIV ELISA (cats) helpful in treatment of diarrhea only is resistant to 5.25% sodium hypochlorite
○ Nitazoxanide successfully used in human (commercial bleach).
Advanced or Confirmatory Testing infections, but dosage for cats and dogs
• Fecal specimens submitted to commercial unknown Technician Tips
laboratories should be sent in 38% form- • Cryptosporidium oocysts are yeastlike in
aldehyde (100% formalin) solution added Chronic Treatment appearance when evaluated on a wet mount.
at a 1 : 10 dilution to kill oocysts but still Treatment of concurrent intestinal dysbiosis/ • The cysts are about 4-6 microns in diameter
allow detection. The oocysts are detected antibiotic-responsive enteritis/small-intestinal (one-half of the diameter of a red blood cell),
after centrifugation using DFA or acid-fast bacterial overgrowth (e.g., metronidazole and oil immersion must be used to detect.
stain. 10-15 mg/kg PO q 12-24h for 5-7 days) (p.
• A DFA kit is available (Merifluor) that 260) may be beneficial in addition to treatment Client Education
detects Cryptosporidia and Giardia oocysts for Cryptosporidium. • Potential for zoonosis
but requires an incubation chamber and • Caution with immunosuppressed individuals
fluorescent microscope for use. Nutrition/Diet and young children (greatest potential for
• Available EIA test kits specific for fecal Feeding a highly digestible diet is recommended infection)
antigen in humans and rodents are difficult in addition to pharmacotherapy in cats with
to use, and acid-fast stain may be just as severe clinical signs of chronic infection. SUGGESTED READING
effective for dogs and cats. Scorza V, et al: Cryptosporidiosis and cyclosporiasis.
• A feline serum cryptosporidial immunoglobu- Possible Complications In Greene CE, editor: Infectious diseases of the
lin G (IgG) enzyme-linked immunosorbent Chronic infection: intestinal intussusception dog and cat, ed 4, St. Louis, 2012, Saunders, pp
assay (ELISA) is available and highly cor- or lymphangiectasia is possible. 840-851.
relates with exposure with parasite but not AUTHOR: Saralyn Smith-Carr, DVM, PhD, DACVIM
necessarily with active infection. Recommended Monitoring EDITOR: Rance K. Sellon, DVM, PhD, DACVIM
• Polymerase chain reaction (PCR) tests • Fecal analysis is recommended after treatment
for detecting cryptosporidial nucleic acids to determine whether oocyst shedding is still
in feces are very sensitive (false-positives occurring.

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