Evaluation of fenbendazole for treatment of Giardia infection in cats concurrently infected with Cryptosporidium parvum.
OBJECTIVE
To determine whether fenbendazole effectively eliminates Giardia organisms from chronically infected cats that have a concurrent Cryptosporidium parvum infection.


METHODS
16 clinically normal cats.


METHODS
Eight cats with chronic concurrent Giardia and C parvum infections received fenbendazole (50 mg/kg, PO, q 24 h) for 5 days (treatment-group cats). Feces from each cat were collected and processed 3 days weekly for 23 days after treatment. By use of an immunofluorescent assay for detection of Giardia lamblia cysts and C parvum oocysts, organism numbers were counted and scored. Fecal results from treatment-group cats were compared with those of 8 untreated cats with Giardia infection but no C parvum infection (control-group cats).


RESULTS
Four of 8 treatment-group cats had consistently negative results for Giardia infection after treatment. These 4 cats had consistently positive results for C parvum oocysts prior to treatment and consistently negative results after treatment. One treatment-group cat had positive results for cysts on all fecal samples, and 3 treatment-group cats had 1 to 3 negative results and then resumed shedding large numbers of cysts; each of these cats had consistently positive results for C parvum oocysts. When compared with control-group cats, treatment-group cats shed less Giardia cysts during week 1 after treatment but not during week 2.


CONCLUSIONS
Administration of fenbendazole decreases Giardia cyst shedding to less than detectable numbers in some cats. In our study, persistent C parvum infection may have been associated with failure of fenbendazole to eliminate Giardia infection.
Keith
Carey L
CL
Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA.
Radecki
Steven V
SV
Lappin
Michael R
MR
D000818:Animals; D000981:Antiprotozoal Agents / Q000627:therapeutic use; D002371:Cat Diseases / Q000188:drug therapy* / Q000469:parasitology; D002415:Cats; D003457:Cryptosporidiosis / Q000188:drug therapy* / Q000662:veterinary*; D016785:Cryptosporidium parvum; D005243:Feces / Q000469:parasitology; D005273:Fenbendazole / Q000627:therapeutic use*; D005873:Giardiasis / Q000188:drug therapy* / Q000662:veterinary*
D000981:Antiprotozoal Agents; D005273:Fenbendazole