Efficacy of ronidazole for treatment of feline Tritrichomonas foetus infection.
OBJECTIVE
To determine the efficacy of ronidazole (RDZ), tinidazole (TDZ), and metronidazole (MDZ) against Tritrichomonas foetus in vitro and of RDZ for treatment of feline naturally occurring or experimentally induced T. foetus infection.


METHODS
A cat naturally infected with T. foetus infection and diarrhea. Ten specific-pathogen-free (SPF) kittens.


METHODS
RDZ, TDZ, and MDZ were tested for activity against 3 different feline isolates of T. foetus in vitro. RDZ then was administered to a naturally infected cat at 10 mg/kg PO q24h for 10 days. SPF kittens were infected orogastrically with feline T. foetus and treated with either placebo or RDZ (10 mg/kg PO q12h for 14 days). Cats with relapsing infection or those receiving placebo were treated subsequently with RDZ (either 30 or 50 mg/kg PO q12h for 14 days). Feces were examined for T. foetus by direct microscopy, culture, and polymerase chain reaction (PCR) testing weekly.


RESULTS
Both RDZ and TDZ killed T. foetus at concentrations >0.1 microg/mL in vitro. In the naturally infected cat, RDZ abolished diarrhea and T. foetus infection for 85 days after treatment, at which time infection and diarrhea relapsed. Retreatment with RDZ eradicated diarrhea and T. foetus infection for over 407 days. In experimentally induced infection, RDZ at 10 mg/kg caused initial improvement, but infection relapsed in all 5 cats 2 to 20 weeks after treatment. At 30 or 50 mg/kg, 10/10 cats were negative for T. foetus infection for follow-up durations of 21 to 30 weeks after treatment.


CONCLUSIONS
Oral administration of RDZ at 30 to 50 mg/kg q12h for 14 days resolved diarrhea and eradicated infection (on the basis of polymerase chain reaction [PCR] testing) in 1 naturally infected cat and 10 experimentally inoculated cats receiving a different isolate of T. foetus.
Gookin
Jody L
JL
Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh 27606, USA. Jody_Gookin@ncsu.edu
Copple
Christina N
CN
Papich
Mark G
MG
Poore
Matthew F
MF
Stauffer
Stephen H
SH
Birkenheuer
Adam J
AJ
Twedt
David C
DC
Levy
Michael G
MG
D000284:Administration, Oral; D000818:Animals; D000981:Antiprotozoal Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D002371:Cat Diseases / Q000188:drug therapy* / Q000382:microbiology / Q000473:pathology; D002415:Cats; D016054:DNA, Protozoan / Q000032:analysis; D003967:Diarrhea / Q000188:drug therapy / Q000382:microbiology / Q000662:veterinary; D005260:Female; D008795:Metronidazole / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D021261:Parasitic Sensitivity Tests; D016133:Polymerase Chain Reaction / Q000662:veterinary; D011528:Protozoan Infections / Q000188:drug therapy / Q000382:microbiology; D011529:Protozoan Infections, Animal; D012385:Ronidazole / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D013047:Specific Pathogen-Free Organisms; D014011:Tinidazole / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D016896:Treatment Outcome; D016835:Tritrichomonas foetus / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification
D000981:Antiprotozoal Agents; D016054:DNA, Protozoan; D014011:Tinidazole; D008795:Metronidazole; D012385:Ronidazole