lasalocid and Cryptosporidiosis

Topics: Animals; Animals, Newborn; Cattle; Cattle Diseases; Coccidiostats; Cryptosporidiosis; Lasalocid; Treatment Outcome

In the first part of the present study, a total of 109 faeces samples collected from calves suffering from diarrhoea were examined for Cryptosporidium parvum oocytes and 39 (35.8%) of them were found to be positive. On the basis of oocyte counts, 14 (36%) samples were assessed as mildly infected and 25 (64%) samples as heavily infected. The occurrence of the disease was more common in winter (56.4%) than during other seasons (autuma 0%, summer 15.4% spring 28.2%. In the present study, the ionophore polyetherantibiotic Lasalocid-Na, that is licensed as a feed additive (Bovatec, 15% Lasalocid-Na, Roche AG) in Turkey, was administered to 11 calves naturally infected with Cryptosporidium and its therapeutic effect was evaluated. Lasalocid-Na (8 mg/ kg BW) was given once daily for 3 days added to the milk. The clinical parameters of infected calves were evaluated before and 3 days after the treatment in 24 hour intervals. The oocyst counts of faeces of calves with cryptosporidiosis were between 15 x 10(6) and 96 x 10(6)/mL before treatment. No oocystes were found in faecal samples of 3 calves (27.3%) after 48 hours and 4 (40%) calves after 72 hours of treatment, respectively. The number of oocytes in the faeces of the remaining calves varied between 90 and 1.2 x 10(6)/mL during the respective period. The number of oocystes before treatment was significantly higher than the number of oocytes after treatment. One of the calves died 56 h after the first treatment despite the treatment. The pH of venous blood was decreased prior to treatment as expected. The lowest pH was 6.83, the lowest bicarbonate concentration was 3.80 mmol/l and the lowest base excess was -31.2 mmol/l. After the treatment, pH, pCO2, HCO3- and BE values of the venous blood increased significantly and reached physiological values before discharge. The differences between the values assessed before the treatment and at the 2nd, 3rd, and 4th sampling time were statistically significant. Number of leucocyte and haemoglobin concentration before the treatment were significantly higher than the values after treatment (p < 0.01). These values returned back to physiological ranges 72 hours after first treatment. Lasalocid-Na was rather well tolerated. Side effects such as the decline of the suckling reflex and intoxication symptoms in respect to present administration form and dosage were found only in one calf (9%). Treatment procedure in the present study with Lasalocid-Na was found to be suitable in

Topics: Animals; Animals, Newborn; Cattle; Cattle Diseases; Coccidiostats; Cryptosporidiosis; Cryptosporidium parvum; Feces; Ionophores; Lasalocid; Oocysts; Seasons; Treatment Outcome; Turkey

In vitro viability of purified Cryptosporidium parvum oocysts, exposed for 30, 60, 90 and 120min to 0.27mg/ml lasalocid suspension was evaluated by inclusion or exclusion of two fluorogenic vital dyes and an excystation technique. Continuously, preventive and curative efficacies at different doses (9, 6.75, 5.625 and 4.5mg/kg body weight) and regimens of lasalocid against cryptosporidial infection were evaluated on an experimental neonatal mice model. In vitro assays demonstrated a decrease in the oocyst viability related to an increase in exposure time for exposure to the lasalocid suspension. The infection was eradicated when the suspension was administered with a dose of > or = 6.75mg/kg body weight. No apparent toxic effects were observed.

Topics: Animals; Animals, Newborn; Coccidiostats; Cryptosporidiosis; Cryptosporidium parvum; Female; Fluorescent Dyes; Indoles; Intestine, Large; Intestine, Small; Lasalocid; Mice; Microscopy, Fluorescence; Microscopy, Phase-Contrast; Parasite Egg Count; Propidium; Statistics, Nonparametric

Repeated outbreaks of cryptosporidiosis in three to fourteen days old calves on a dairy farm gave rise to a detailed description of the induced therapeutic, epidemiological and prophylactic measures. In farms with ongoing problems of diarrhea in calves, its etiology should be cleared. For cryptosporidiosis, which can not be cured by a conventional symptomatic treatment, only Lasalocid-Na is available. In Switzerland the ionophoric polyether antibiotic Lasalocid-Na is available as a food additive (Bovatec, 15% Lasalocid-Na, Hoffmann-La Roche AG). After the establishment of a diagnosis it must be administered as follows: 2 x 6 mg/kg BW, i.e. 2 x 40 mg Bovatec/kg BW, daily for three days. The recommended dose has to be respected because of a very high risk of intoxication. Moreover, on contaminated farms strict measures of hygiene, disinfection and cleaning have to be respected. Calving cows have to be kept separated during the calving period and the newborn calves must be separated from the adult cattle unit.

Topics: Animals; Animals, Newborn; Cattle; Cattle Diseases; Coccidiostats; Cryptosporidiosis; Disease Outbreaks; Female; Ionophores; Lasalocid; Switzerland

Lasalocid, sinefungin, and dehydroepiandrosterone were tested for anticryptosporidial activity with an immunodeficient mouse model at doses that have been reported effective when tested with immunosuppressed rodent models. Small but significant reductions in oocyst excretion were only observed under some conditions with lasalocid and dehydroepiandrosterone, but sinefungin had no effect.

Topics: Adenosine; Animals; Antiprotozoal Agents; Coccidiostats; Cryptosporidiosis; Cryptosporidium parvum; Dehydroepiandrosterone; Immunologic Deficiency Syndromes; Lasalocid; Male; Mice; Mice, Nude; Splenectomy

Cryptosporidium parvum causes life-threatening diarrhoea in immunocompromised, especially AIDS patients and the efficiency of proposed anti-cryptosporidial therapies is limited or doubtful. An immunosuppressed adult rat model of C. parvum infection was developed for screening molecules candidate for curative and preventive activity in human cryptosporidiosis. Among 31 drugs tested, lasalocid (2-10 mg/kg/24 h), and sinefungin (2-10 mg/kg/24 h), exhibited some activity against C. parvum infection. Oral sinefungin therapy resulted in a dose related suppression of oocysts shedding, which correlated with oocyst disappearance from ileum sections and was also efficient in preventing infection. Relapses were observed after discontinuation of curative sinefungin therapy, which suggests that the biliary tract, a major location and parasite reservoir which sustains persisting infection, was not cleared of parasites by the drug. Improved therapeutic procedures with sinefungin (or analogues) will result from current pharmacological studies.

Topics: Adenosine; Animals; Coccidiostats; Cryptosporidiosis; Cryptosporidium parvum; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Feces; Immunocompromised Host; Lasalocid; Male; Rats; Rats, Sprague-Dawley

The anticryptosporidial activities of three ionophorous antibiotics were assessed in dexamethasone-immunosuppressed rats infected with Cryptosporidium parvum. When administered prophylactically, lasalocid prevented infection in a dose-dependent manner, whereas monensin and salinomycin were ineffective. Therapeutically, lasalocid eliminated established overt infections of the intestine, although infection persisted in the common bile duct and intestinal infection recurred after lasalocid treatment was stopped. These findings suggest that lasalocid is a potentially useful anticryptosporidial agent but that long-term continuous administration may be necessary in the immunocompromised host.

Topics: Animals; Cryptosporidiosis; Cryptosporidium parvum; Female; Immunocompromised Host; Ionophores; Lasalocid; Monensin; Pyrans; Rats; Rats, Sprague-Dawley

Chemoprophylaxis of Cryptosporidium baileyi infections was attempted by feeding 4 groups of chicks diets containing 3 mg of halofuginone/kg of feed, 60 mg of salinomycin/kg, 75 mg of lasalocid/kg, or 110 mg of monensin/kg. Rations were fed 5 days before oral or intratracheal inoculation with oocysts and were continued for 20 days. None of the drugs prevented C baileyi infections. Clinical signs of respiratory tract disease and gross lesions of airsacculitis were observed in intratracheally inoculated birds in all treatment groups and nonmedicated controls. Orally inoculated birds did not develop clinical signs of infection. Pathogenic bacteria were not isolated from the respiratory tract systems of any chicks. Halofuginone delayed the establishment of infections of the bursa of Fabricius and cloaca, but not of the trachea.

Topics: Animals; Chickens; Coccidiostats; Cryptosporidiosis; Lasalocid; Monensin; Piperidines; Poultry Diseases; Pyrans; Quinazolines; Quinazolinones