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This article summarises the current knowledge of the rabbit coccidia and the disease they cause. Various aspects, such as life cycles, localisation in the host, pathology and pathogenicity, immunity and control, are discussed.

A series of experiments have been undertaken to determine the effect of water extracts from pine bark (Pinus radiata) on the inhibition of the sporulation of oocysts of three species of avian coccidia. Tubes containing coccidian oocysts isolated from droppings of coccidia-infected chickens were randomly assigned to 0, 250, 500 and 1,000 microg/mL pine bark extract (PBE). The tubes were incubated at 25-29 deg C for 48 h depending on the species of Eimeria. Sporulation inhibition bioassay was used to evaluate the activity of PBE on the sporulation of coccidian oocysts. The oocysts were gently aerated with an air pump away from sun light. The results show for the first time that water-soluble extracts from pine bark containing 35% condensed tannins have anticoccidial activity as evidenced by their ability to decrease significantly the sporulation of the oocysts of three species of Eimeria, namely Eimeria tenella, E. maxima and E. acervulina, under laboratory conditions. Incubation of unsporulated oocysts of these parasites in water containing 500 microg PBE per mL resulted in inhibition of sporulation of these oocysts by about 28-84% relative to the oocysts in the control incubations. In addition, up to 12% of E. maxima oocysts exposed to 500-1,000 microg pine bark/mL were containing abnormal sporocysts in terms of size, number and shape.

Microorganisms produce low-molar-mass secondary metabolites exhibiting different biological activities, which are used e.g. in medicine as antimicrobial and antifungal agents, alkaloids and toxins. Some of these substances have highly diverse biological activities and unusual structures. They are produced by streptomycetes, fungi, and bacilli, but interesting products have also been obtained from microorganisms growing in extreme conditions. Several thousands of microbial products have so far been discovered and many other, which can be potentially useful and/or prospective for human use, can still be in the offing. Special chapters of this article deal with inhibitors of enzymes splitting antibiotics, inhibitors of peptidases, inhibitors of lipases, cancerostatics, inhibitors of protein kinases, coccidiostatics, antiparasitics, herbicides, antioxidants, immunosuppressants, and antiviral compounds.

Diclazuril is a benzeneacetonitrile anticoccidial that is also effective in the prevention of toxoplasmosis. The present study was conducted to examine the efficacy of diclazuril alone or in combination with pyrimethamine for the treatment of acute toxoplasmosis in mice. Diclazuril administered at 10 mg/kg beginning 6 days after inoculation and given for 10 days protected 90% of mice over a 56-day observation period. Treatment with diclazuril at 1.0 or 0.5 mg/kg protected 20 and 0% of mice, respectively. Treatment with pyrimethamine at 12.5 or 6.0 mg/kg protected 60 and 0% of mice, respectively. When diclazuril (1.0 or 0.5 mg/kg) was combined with pyrimethamine (12.5 mg/kg) all mice survived the 56-day observation period. When diclazuril (1.0 or 0.5 mg/kg) was combined with pyrimethamine (6.0 mg/kg) 30 and 10% of mice, respectively, survived the 56-day observation period.

Coccidia were isolated from 122 Belgian broiler farms without clinical coccidiosis. Shuttle programs including robenidine or nicarbazin in the starter (7-14 days) followed by an ionophore or diclazuril in the grower ration were most commonly used. Out of 215 coccidiosis-positive groups, 146 Eimerta acervulina, 65 E. maxima, and 88 E. tenella isolates were tested without further laboratory propagation in 17 sensitivity profiles. For each profile, oocysts were pooled from 9 +/- 4 farms (X +/- SD) that used the same anticoccidial program and that belonged to the same integrated broiler operation. Each suspension contained an equal number of isolates and oocyst numbers from each farm tested. Each profile included an unmedicated uninfected group, an unmedicated infected group, and 11 medicated infected groups, consisting each of three replicates of three Ross chicks Medication started at 8 days of age, and each inoculated bird received 50,000 sporulated oocysts at 10 days. Results were related to the anticoccidial program that had been in use. Chemical drugs showed the highest activity against Eimeria, whereas ionophores were less efficacious. Of the latter, monensin (110 ppm) was least active; narasin (70 ppm), salinomycin (60 ppm), and maduramicin (5 ppm) took an intermediate position, and lasalocid (90 ppm) was most active. A 50% improvement in weight gain was obtained in 7 to 10 out of 17 profiles with 100 + 8.35 ppm clopidol/methylbenzoquate (10),125 ppm nicarbazin (9), 3 ppm halofuginone (8), and 1 ppm diclazuril (7). A 50% improvement in feed conversion was obtained in 7 to 11 profiles with nicarbazin (11), halofuginone (10), diclazuril (9), 33 ppm robenidine (9), clopidol/methylbenzoquate (7), and lasalocid (7). Based on relative oocyst output, the highest activity against E. acervulina was obtained with clopidol/methylbenzoquate (8/16); the highest activity against E. maxima was obtained with lasalocid (6/6), diclazuril (5/6), and halofuginone (5/6).

Nine enzymes were detected in sporulated oocysts of Eimeria tenella and E. maxima, parasites of the domesticated fowl (Gallus gallus). Three enzymes, hydroxybutyrate dehydrogenase, alanine aminotransferase and gamma-glutamyltransferase, all identified for the first time in Eimeria of fowl, occurred both in E. tenella and in E. maxima. The remaining enzymes assayed had previously been found in various Eimeria species of fowl, although creatine kinase and glutamate dehydrogenase were hitherto unknown from E. maxima. The three enzymes newly recorded from Eimeria of fowl are of interest as potential genetic markers, and also as potential chemotherapeutic targets. The discovery of hydroxybutyrate dehydrogenase led to the demonstration of anticoccidial activity by some aliphatic acids. The paper also includes a list of the enzymes detected in Eimeria of fowl in previous studies.

One-day-old leghorn chicks were placed in floor pens on previously used poultry litter (potentially providing exposure to normal chicken enteric flora) for 7 days and provided feed containing one of several antibiotics or anticoccidials. On day 7, all groups were challenged orally with an isolate of Salmonella enteritidis (10(6) colony-forming units) that was resistant to bacitracin, novobiocin, nalidixic acid, and nitrofurazone. All chicks were killed on day 13, and liver, spleen, and cecal tonsils were cultured. Dietary administration of novobiocin (0.385 g/kg) caused a significant increase (P < 0.05) in positive chick colonization rate (either liver and spleen or cecal tonsils) compared with the unmedicated controls. Similarly, chicks administered dietary nitrofurazone (0.3 g/kg) were infected with S. enteritidis at a significantly greater frequency than the unmedicated controls. A significant decrease in cecal volatile fatty acid concentration, previously shown to influence susceptibility to selected enteric pathogens, was observed in the novobiocin- and nitrofurazone-treated groups. Treatment with chlortetracycline (11.4 g/kg), monensin (0.91 g/kg), or nicarbazin (0.49 g/kg) had no effect on S. enteritidis invasion or colonization. Bacitracin (0.49 g/kg) significantly increased S. enteritidis cecal colonization rate when administered continuously throughout the study. These data support and extend previous investigations involving other salmonellae and indicate that selected antibiotics may increase the severity and frequency of S. enteritidis colonization and invasion rate in leghorn chicks.

An immunosuppressed mouse model was used to determine the effects of amprolium and sulfadiazine on experimental Neospora caninum infections. Both drugs were given in the drinking water. Neither drug was effective in treating infections when given 7 days after inoculation of tachyzoites, when clinical signs of disease had developed. Amprolium did not prevent deaths or development of clinical signs when given in the drinking water at 1 mg/ml or 5 mg/ml 3 days after inoculation of tachyzoites. Sulfadiazine in drinking water was not effective when given at 0.5 mg/ml but was effective in preventing deaths and clinical disease when given at 1 mg/ml 3 days after inoculation with tachyzoites. Most mice (6 of 10) treated for 3 days with 1 mg/ml sulfadiazine in drinking water developed encephalitis after drug treatment was stopped. Treatment for 14 days with 1 mg/ml sulfadiazine in drinking water was needed to protect 90% of inoculated mice.