Report of the first clinical case of intestinal trichomoniasis caused by Tritrichomonas foetus in a cat with chronic diarrhoea in Brazil.

BACKGROUND: Tritrichomonas foetus is an emergent and important enteric pathogen of cats, which causes prolonged diarrhoea in cats. CASE PRESENTATION: This study describes a T. foetus infection in a seven-month-old, entire male domestic shorthair kitten with a six-month history of persistent large intestinal diarrhoea, faecal incontinence, prostration, apathy and weight loss. Parasites were microscopically observed and confirmed by PCR and DNA sequencing. Molecular analyses were carried out comparing the sequence obtained in this study with T. foetus and T. suis. Retrieved from GenBank. After treatment with ronidazole, the cat showed resolution of clinical signs. CONCLUSIONS: This is the first clinical case of T. foetus infection in a chronic diarrheic cat in Brazil and South America, confirming the presence of this pathogen in this part of the world and highlighting the importance of this protozoa being considered in the differential diagnosis of cats presenting diarrhoea of the large intestine. Our case report enriches our knowledge on the geographical distribution of T. foetus in cats in Brazil and provides further understanding of the clinical significance of feline intestinal trichomoniasis in this country.

Ronidazole pharmacokinetics in cats following delivery of a delayed-release guar gum formulation.

Ronidazole (RDZ) is the only known effective treatment for feline diarrhea caused by Tritrichomonas foetus. This study aimed to develop guar gum-coated colon-targeted tablets of RDZ and to determine the pharmacokinetics of this delayed-release formulation in cats. Guar gum-coated tablets were administered orally once to five healthy cats (mean dose 32.3 mg/kg). The tablets were then administered once daily for 5 days to four cats (mean dose 34.5 mg/kg), and absorption studies repeated on day 5. Plasma was collected and analyzed for RDZ concentration, and pharmacokinetic noncompartmental and deconvolution analysis were performed on the data. There was negligible RDZ release until after 6 h, and a delayed peak plasma concentration (mean Cmax 28.9 µg/mL) at approximately 14.5 h, which coincides with colonic arrival in cats. Maximum input rate (mg/kg per hour) occurred between 6 and 16 h. This delayed release of ronidazole from guar gum-coated tablets indicates that release of RDZ may be delayed to deliver the medication to a targeted area of the intestine. Repeated dosing with guar gum tablets to steady-state did not inhibit drug bioavailability or alter the pharmacokinetics. Such targeted RDZ drug delivery may provide improved efficacy and reduce adverse effects in cats.

Efficacy of ronidazole for treatment of cats experimentally infected with a Korean isolate of Tritrichomonas foetus.

To evaluate the efficacy of ronidazole for treatment of Tritrichomonas foetus infection, 6 Tritrichomonas-free kittens were experimentally infected with a Korean isolate of T. foetus. The experimental infection was confirmed by direct microscopy, culture, and single-tube nested PCR, and all cats demonstrated trophozoites of T. foetus by day 20 post-infection in the feces. From day 30 after the experimentally induced infection, 3 cats were treated with ronidazole (50 mg/kg twice a day for 14 days) and 3 other cats received placebo. Feces from each cat were tested for the presence of T. foetus by direct smear and culture of rectal swab samples using modified Diamond's medium once a week for 4 weeks. To confirm the culture results, the presence of T. foetus rRNA gene was determined by single-tube nested PCR assay. All 3 cats in the treatment group receiving ronidazole showed negative results for T. foetus infection during 2 weeks of treatment and 4 weeks follow-up by all detection methods used in this study. In contrast, rectal swab samples from cats in the control group were positive for T. foetus continuously throughout the study. The present study indicates that ronidazole is also effective to treat cats infected experimentally with a Korean isolate of T. foetus at a dose of 50 mg/kg twice a day for 14 days.

Efficacy of guar gum-based ronidazole capsules as a treatment for Tritrichomonas foetus infection in cats.

Objectives The aims of the study were to determine the in vitro drug release of guar gum-coated capsules of ronidazole, and to evaluate the pharmacokinetics and efficacy of this formulation for the treatment of cats naturally infected with Tritrichomonas foetus. Methods The pharmacokinetics of ronidazole were evaluated in five healthy cats and five cats infected with T foetus. In a second step, the clinical efficacy of these capsules was evaluated by a controlled, randomised, double-blind clinical trial performed in 47 infected cats from French catteries. In this study, cats were randomly allocated to either the ronidazole treatment group (n = 25) or a placebo group (n = 22). Ronidazole (30 mg/kg) q24h for 14 days was administered to the treated cats. After 14 days of treatment, the presence of T foetus was tested by conventional PCR assay. Results In the pharmacokinetic study, a delayed peak plasma concentration was observed in healthy and infected cats, with no significant difference between these two groups (mean geometric mean of 9 h for time to maximum plasma concentration [Tmax], 21.6 µg/ml for time to maximum plasma concentration [Cmax] and 467.4 µg/h/ml for the area under the curve [AUC] in healthy cats; and 9.4 h for Tmax, 17.1 µg/ml for Cmax and 481 µg/h/ml for AUC in infected cats). In the clinical trial, T foetus was detected in 16% of cats from the treated group and 82% of cats from the placebo group at the end of the study ( P <0.001). No clinical signs of adverse drug reactions were observed. Conclusions and relevance Oral administration of guar gum-coated capsules of ronidazole at a dose of 30 mg/kg once daily for 14 days delays the peak plasma concentration and eradicates infection in most cases.

Transfer of nitroimidazoles from contaminated beeswax to honey.

Nitroimidazoles are not authorised for the treatment of honey bees in the European Union. However, they can be found in honey largely because they are illegally used in apiculture for the treatment of Nosema. The aim of the study was to examine the possible transfer of nitroimidazoles (metronidazole, ronidazole, dimetridazole and ipronidazole) from contaminated beeswax to honey. The wax foundations fortified with a mixture of four nitroimidazoles at three concentration levels (1000, 10,000 and 100,000 µg kg-1) were placed in beehives to let the honeybees (Apis mellifera L.) draw out the contaminated wax foundations to honeycombs. At 1 month from the start, the frames filled with capped honey were removed from the hives for a first sampling of honey. Next, the honeycombs were further incubated for 5 months in the laboratory at 35°C and sampled monthly. In the sampled honey, the concentrations of nitroimidazoles and their main metabolites (hydroxymetronidazole, 2-hydroxymethyl-1-methyl-5-nitroimidazole, hydroxyipronidazole) were determined by LC-MS/MS and compared with those determined in the nitroimidazole-containing wax foundations. Each of the tested nitroimidazoles could migrate from beeswax to honey kept in the contaminated combs at each tested concentration level. Higher maximum concentrations of residues in honey sampled from contaminated combs at 1000, 10,000 and 100,000 µg kg-1 were observed for metronidazole (28.9, 368.5 and 2589.4 µg kg-1 respectively) and ronidazole (27.4, 232.9 and 2351.2 µg kg-1 respectively), while lower maximum concentrations were measured for dimetridazole (0.98, 8.4 and 67.7 µg kg-1) and ipronidazole (0.9, 7.9 and 35.7 µg kg-1 respectively). When we took into account that a frame completely filled with honey on both sides of the comb contained 110 g of beeswax and 2488 g of honey, and that this ratio was constant, then maximum amounts of initial metronidazole, ronidazole, dimetridazole and ipronidazole that migrated from contaminated wax foundations to honey could be calculated: 65-89%, 55-63%, 1.7-2.7% and 1.4-2.3%, respectively.

Efficacy of ronidazole for treatment of feline Tritrichomonas foetus infection.

OBJECTIVES: 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. ANIMALS: A cat naturally infected with T. foetus infection and diarrhea. Ten specific-pathogen-free (SPF) kittens. PROCEDURE: 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 AND CLINICAL RELEVANCE: 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.

Design and evaluation of a novel chitosan-based system for colon-specific drug delivery.

Tritrichomonas foetus is a flagellated protozoan parasite that colonizes the feline colon causing colitis and chronic foul smelling diarrhoea. Despite the efficacy of Ronidazole in the treatment of T. foetus, Ronidazole has been reported to cause neurotoxicity in some cats due to rapid absorption in the small intestine. A novel amphoteric derivative of chitosan was synthesised and characterized. A combination of time, pH, and an enzyme controlled system was used in a study of a new compression coated tablet for delivery of Ronidazole to the colon. Axial, radial swelling and erosion of selected tablets were carried out in various media. The effect of weight ratio, enzyme and pH on in vitro drug release profile was investigated. The results show that less than 2% of the drug was released in the physiological environment of the stomach and small intestine.

Use of Ronidazole and Limited Culling To Eliminate Tritrichomonas muris from Laboratory Mice.

Tritrichomonas muris is occasionally identified during routine fecal screening of laboratory mice. Frequently, entire racks are affected, and because no effective treatment is available, culling of affected mice and rederivation by embryo transfer have been suggested. The current study evaluated whether treatment with ronidazole, a nitroimidazole efficacious against T. fetus infections in cats, combined with limited culling was effective against T. muris in laboratory mice (Mus musculus). A subset (n = 39) of mice were treated with ronidazole (400 mg/L in drinking water) for 15 d, after which 6 of the mice still shed T. muris. Consequently all mice in the affected rack received ronidazole (500 mg /L in drinking water) for 25 d. All mice were retested by using pooled samples, and those positive for T. muris (except for a valuable breeding pair) were culled. The remaining mice continued to receive ronidazole for another 17 d. At the end of the treatment period, all mice were tested (days 60 and 81) and were shown to be negative for T. muris. Over the following year, sentinel mice from the rack were tested every 3 mo and remained negative for tritrichomonads by fecal smear. Thus, a combination of limited culling and treatment with ronidazole in the drinking water successfully cleared research mice of infection with T. muris.

[Treatment of Tritrichomonas foetus in a cat colony with delayed release ronidazole tablets in the small intestine]. / Behandlung einer an Tritrichomonas foetus erkrankten Katzen-Kolonie mittels Ronidazoltabletten unter verzögerter Wirkstofffreisetzung im Dünndarm.

Seven abyssinian cats (two male, five female) showed intermittent green-yellow mucous diarrhoea, sometimes an inflammation of the anal region and faecal incontinence even after long-time treatment with fenbendazole against Giardia. During necropsy of one of the cats, which had to be euthanized due to another disease, the gut wall of small and large intestine appeared macroscopically thickened. Histological examination indicated flagellates in the lumen of the intestine (initiating at the jejunum) and in the crypts. However Giardia could be excluded. in this case. By PCR of the faeces Tritrichomonas (T) foetus was diagnosed in five of six cats of this colony. Five remaining animals (another cat had to be euthanized) were treated with about 30 mg per kg BW ronidazole p. o. (rededication; Ridzol 10% Bt®, Dr. Hesse Tierpharma GmbH & Co. KG, Germany) daily over 14 days. The special gastro-resistant processing of the ronidazole should ensure a targeted effects. Animals were treated consecutively, isolated from the other cats and were daily examined clinically and neurologically. Neurotoxic adverse effects appeared slightly, therefore--as a precaution--the treatment of two cats was paused for one day. After treatment of all cats, T. foetus wasn't diagnosed by PCR over the period of 345 to > 800 days in any cat. One animal had dubious findings in the ninth week after treatment. Hence it was still kept isolated from the group and PCR showed a negative result at all times afterwards. The treatment protocol shows that elimination of problematic protozoal infections is possible in cat colonies.

Ronidazole in high concentrations in drinking water for treatment and prevention of diarrhea in swine dysentery.

Ronidazole administered in the drinking water at concentrations of 0.012, 0.006, and 0.003% was effective for the treatment of swine dysentery. All groups of medicated swine had more survivors, fewer days of hemorrhagic and nonhemorrhagic diarrhea, greater feed consumption, greater weight gain, and more favorable feed efficiency than did nonmedicated swine. The only adverse clinical sign and lesion observed in the medicated swine comprised the drug-delayed-augmented swine dysentery which affected 3 swine in a group given 0.003% ronidazole. Several of the swine given the 0.012% concentration developed nonhemorrhagic diarrhea while on medication, probably because of the high concentration of the drug. Diarrhea did not recur in swine after the withdrawal of medication in both of 2 groups given the 0.012% concentration, in 3 of 4 groups given the 0.006% concentration, or in 1 of 4 groups given the 0.003% concentration. One or more swine were susceptible to reexposure to swine dysentery in both groups given the 0.012% concentration, in 1 group given the 0.006% concentration and in 1 group given the 0.003% concentration. Large spirochetes were observed in fecal smears from all exposed swine which developed either hemorrhagic or nonhemorrhagic diarrhea.

Ronidazole in low concentrations in drinking water for treatment and development of immunity to swine dysentery.

The addition of ronidazole to the drinking water at the concentration of 0.003% was effective for the treatment of experimentally induced swine dysentery in swine. Ronidazole at concentrations of 0.0015% and 0.00075% aided in the treatment of swine dysentery and the development of immunity to the disease. In experiment I, in which swine were given concentrations of 0.003, 0.0015, and 0.00075%, there were more survivors, fewer days of hemorrhagic diarrhea, greater feed and water consumption and body weight gain, and more favorable feed efficiency in the medicated swine than in the nonmedicated swine. With the 0.003% concentration, there were no deaths, and the diarrhea receded during or after treatment with the 0.0015% and 0.00075% concentrations, the incidence of nonhemorrhagic diarrhea was greater in medicated than in nonmedicated swine, and the diarrhea did not subside during treatment. In experimetn II, there were more survivors in the groups of swine medicated with the 0.0015% concentration than in the nonmedicated groups of swine. All surviving nonmedicated swine in experiment I were immune to reexposure 3 months after initial exposure. More swine given to the 0.0015% and 0.00075% concentrations in the same experiment were immune to reexposure 3 months after initial exposure than were the swine given the 0.003% concentration. In experiment II, neither the swine previously medicated with the 0.0015% concentration nor the nonmedicated swine were immune to reexposure 5 weeks after initial expsoure. Large spirochetes were observed in fecal smears from all exposed swine which developed either hemorrhagic or nonhemorrhagic diarrhea.

Influence of level, timing and duration of ronidazole water medication on histomoniasis in turkeys.

Levels of 20, 30, 40, 60 and 120 parts per million (p.p.m.) of ronidazole in water were evaluated for therapeutic efficacy against histomoniasis. Three experiments were conducted with Broad Breasted Bronze and/or Large White poults four to nine weeks old. All poults except the unexposed controls were each given approximately 70 or 100 embryonated Heterakis gallinae ova containing Histomonas meleagridis. Ronidazole medications were administered during the following post-exposure periods: 7-13, 7-17, 10-17, 10-20, 10-23, 10-26, 14-20 and 14-24 days. Histomoniasis mortality and lesions were recorded in each experiment during a 28 or a 35-day post-exposure period. Level of ronidazole, timing and duration of medication significantly affected efficacy. Treatments involving 30 to 40 p.p.m. (or more) of ronidazole, initiated 10 days post-exposure and continued for at least 7-10 days were most effective.

Ronidazole in the treatment and prophylaxis of experimental swine dysentery.

Experimental swine dysentery was produced in groups of susceptible pigs by feeding pure cultures of two isolates of T hyodysenteriae. These infected groups of pigs were then used to assess the efficacy of ronidazole medication of the drinking water and of the feed in the treatment and prophylaxis of the experimental disease. Ronidazole was found to be effective in the treatment of swine dysentery and appeared to eliminate the causal agent, T hyodysenteriae, from treated affected pigs when given in the drinking water at 30 and 60 ppm for three days and in the feed at 120 ppm for four days. The inclusion of ronidazole in the feed for 14 days at 30, 60 and 90 ppm was found to suppress the development of the disease but 90 ppm was the only level found to prevent the development of infection.

[The compatibility of ronidazol in racing pigeons in a controlled clinical study]. / Verträglichkeit von Ronidazol bei Brieftauben im kontrollierten klinischen Test.

Ronidazol is often used in racing pigeons for the treatment of Trichomonas infections and diseases. Therefore, in this study, the compatibility of the drug was examined by oral application over 7 days. For this purpose a randomized blind study was performed using four different groups (control group, 10 mg = therapy-group, 20 mg = double-dose-group and 40 mg = high-dose-group) of pigeons (Columba livia f. domestica) with 6 male and 6 female birds each. All birds were clinically healthy and between 6 and 12 weeks of age. The application of ronidazol at a dose of 10 mg/racing pigeon did show no side-effect within the duration of the study, e.g. no influence could be seen on clinical, haematological, blood-chemical and pathological parameters. Low-to middle-grade clinical alterations of the gastro-intestinal tract occurred in the high-dose group at day 6 and 7 of the application of the drug. Therefore a fourfold overdosing of ronidazol should be avoided.

Ronidazole pharmacokinetics after intravenous and oral immediate-release capsule administration in healthy cats.

Ronidazole (RDZ) is an effective treatment for feline Tritrichomonas foetus infection, but has produced neurotoxicity in some cats. An understanding of the disposition of RDZ in cats is needed in order to make precise dosing recommendations. Single-dose pharmacokinetics of intravenous (IV) RDZ and immediate-release RDZ capsules were evaluated. A single dose of IV RDZ (mean 9.2mg/kg) and a 95mg immediate-release RDZ capsule (mean 28.2mg/kg) were administered to six healthy cats in a randomized crossover design. Plasma samples were collected for 48 h and assayed for RDZ using high pressure liquid chromatography (HPLC). Systemic absorption of oral RDZ was rapid and complete, with detection in the plasma of all cats by 10 min after dosing and a bioavailability of 99.64 (±16.54)%. The clearance of RDZ following IV administration was 0.82 (±0.07) ml/kg/min. The terminal half-life was 9.80 (±0.35) and 10.50 (±0.82) h after IV and oral administration, respectively, with drug detectable in all cats 48h after both administrations. The high oral bioavailability of RDZ and slow elimination may predispose cats to neurotoxicity with twice-daily administration. Less frequent administration should be considered for further study of effective treatment of T foetus-infected cats.

Efficacy of Ronidazole for Treatment of Cats Experimentally Infected with a Korean Isolate of Tritrichomonas foetus

To evaluate the efficacy of ronidazole for treatment of Tritrichomonas foetus infection, 6 Tritrichomonas-free kittens were experimentally infected with a Korean isolate of T. foetus. The experimental infection was confirmed by direct microscopy, culture, and single-tube nested PCR, and all cats demonstrated trophozoites of T. foetus by day 20 post-infection in the feces. From day 30 after the experimentally induced infection, 3 cats were treated with ronidazole (50 mg/kg twice a day for 14 days) and 3 other cats received placebo. Feces from each cat were tested for the presence of T. foetus by direct smear and culture of rectal swab samples using modified Diamond's medium once a week for 4 weeks. To confirm the culture results, the presence of T. foetus rRNA gene was determined by single-tube nested PCR assay. All 3 cats in the treatment group receiving ronidazole showed negative results for T. foetus infection during 2 weeks of treatment and 4 weeks follow-up by all detection methods used in this study. In contrast, rectal swab samples from cats in the control group were positive for T. foetus continuously throughout the study. The present study indicates that ronidazole is also effective to treat cats infected experimentally with a Korean isolate of T. foetus at a dose of 50 mg/kg twice a day for 14 days.

Pharmacokinetics and bioavailability of ronidazole from a prolonged release tablet in the homing pigeon (Columba livia).

The pharmacokinetics of ronidazole and the bioavailability of a prolonged release tablet were studied in the homing pigeon. After intravenous administration of 5 mg ronidazole, the drug plasma concentration profile fitted a one-compartment open model. The mean half-life of the drug was 11 h and the volume of distribution was 0.86 l/kg. Total body clearance was 0.056 l/h/kg. A sustained release matrix tablet exhibited prolonged drug release in vitro. After oral administration of the matrix tablet to pigeons drug absorption was nearly complete. When given on an empty stomach, the tablet failed as a prolonged release system. Administration to previously fed pigeons resulted in an increase in tmax and a decrease in Cpmax.

Influence of feeding on the bioavailability of ronidazole prolonged-release formulations in pigeons.

The influence of feeding on the bioavailability of ronidazole (5 mg per animal) formulated as a hydrophilic-matrix tablet or as lipophilic pellets, was evaluated in pigeons. Administered to fed pigeons, prolonged drug absorption was obtained for both formulations. In non-fed pigeons an immediate grinding of the formulations in the gizzard resulted in rapid drug absorption. This indicates that prolonged residence of the prolonged-release formulations in the crop obtained in the fed condition seemed the only possible means of obtaining prolonged drug release in pigeons.

In vitro nitroimidazole resistance of Trichomonas gallinae and successful therapy with an increased dosage of ronidazole in racing pigeons (Columba livia domestica).

Six out of eight different Trichomonas gallinae strains isolated from racing pigeons proved to be resistant to the nitroimidazole drugs ronidazole, carnidazole and metronidazole. The minimal cytocidal concentration of ronidazole was determined in in vitro experiments. Moreover, a therapeutic dose for ronidazole was determined for the control of trichomoniasis in pigeons from which the resistant T. gallinae strains were isolated. It was a 5-fold increase of the recommended ronidazole dosage which eliminated the infection in affected pigeons.