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The ultrastructural morphology of the different endogenous stages of Eimeria maxima and E. brunetti was evaluated after oral treatment of inoculated chickens with a single dose of 5 mg/kg diclazuril. The drug induced no ultrastructural change in the growth or differentiation of the various schizont stages of both Eimeria spp. In E. maxima, the micromorphological appearance of micro- and macrogamonts developing from the blast form to maturation also remained unaffected by drug treatment. However, in all fertilized macrogamonts the normal pattern of oocyst wall establishment was completely disturbed, resulting in the formation of an abnormally thickened, incomplete oocyst wall and the necrosis of the zygote. In E. brunetti, the growth and nuclear division during microgametogenesis were not affected but differentiation was clearly abnormal. In comparison with the controls, this abnormal differentiation was characterized by a less extensive enlargement of the parasite surface area, aberrant morphological configurations of condensed heterochromatin, intracytoplasmic flagella formation, and glycogen accumulation. Finally, the complete degeneration of all microgamonts ensued. The growth and differentiation leading to mature macrogamonts was not disturbed; however, subsequent oocyst wall formation was largely precluded and the macrogamonts proceeded to degenerate completely. We conclude that diclazuril treatment primarily affected particular stages in the sexual development of both Eimeria spp., resulting in the complete eradication of these coccidian species. [ABSTRACT FROM AUTHOR]

A total of 50 jirds ( Meriones unguiculatus) were infected by intraperitoneal implantation of 0.20 g metacestode tissue of Echinococcus multilocularis. The feed of 4 groups of 10 animals each was treated for 35 days with 500 ppm albendazole, flubendazole, mebendazole or praziquantel; 1 group of 10 jirds served as unmedicated controls. At autopsy 2 weeks after the end of medication, the transplants had increased in size and weight, reaching a total weight of 78.11 g in the control group, 21.60 g in the albendazole-treated group, 3.63 g in the flubendazole-treated group, 7.00 g in the mebendazole-treated group and 68.91 g in the praziquantel-treated group. The percentage in reduction of parasitic tissue weight as compared with control values was 72%, 95%, 91% and 12%, respectively. The calculated daily drug intake was approximately 48 mg/kg body weight. Drug-related side effects were not observed. [ABSTRACT FROM AUTHOR]

The effect of closantel (10 mg/kg orally) and triclabendazole (10 mg/kg orally) on the reappearance of a patent infection of Fasciola hepatica was studied in experimentally infected sheep. The treatments resulted in the interruption of faecal egg output for 11 weeks with triclabendazole and 13 weeks with closantel. Necropsy of untreated control animals revealed a mean burden of 360 flukes with a mean (+/- se) surface area of 171 +/- 64.3 mm2, whereas the fluke burdens in the closantel and triclabendazole-treated animals 14 weeks after treatment were 61 (83 per cent reduction) and 21 (94 per cent reduction), respectively. The surface areas of the flukes in the triclabendazole-group were comparable with the untreated controls (141 +/- 51.8 mm2), but the flukes in the closantel group were markedly smaller (43.1 +/- 26.9 mm2). It is concluded that closantel has, in epidemiological terms, a potency comparable with that of triclabendazole, despite its slightly lower efficacy against the very immature stages.

Diclazuril, a new anticoccidial drug, was tested in young pheasants artificially infected with the three most common pathogenic species of Eimeria, E colchici, E duodenalis and E phasiani. In two replicate experiments each with 40 birds the mortalities in the infected controls were 50 and 25 per cent. Diclazuril was administered in the feed at dose levels of 1, 2 and 4 ppm from the day before the inoculation of coccidia until the end of the test on day 6 after infection. The 1 ppm dose failed to inhibit the development of the parasite completely, as was shown by a reduction of the weight gain of the birds and the output of a small number of oocysts. Diclazuril at 2 or 4 ppm adequately controlled the infection, with weight gains similar to those of the uninfected controls. At all dose levels, mortality, intestinal lesions and diarrhoea were prevented.

Toxocara vitulorum, a parasite of suckling calves, was again diagnosed in Belgium in imported cattle of French origin. The infectious larvae are present in the milk and colostrum; they do not undergo further migration in the tissues of calves. This form of transmammary migration is not specific of T. vitulorum, but was also reported in S. ransomi in pigs. Treatment with levamisole at a dosage of 5 mg/kg results in complete disappearance of the worms. In addition to the cycles, the elements of a specific parasitological diagnosis are also described.

The effectiveness of clazuril (Appertex), a new anticoccidial agent for the treatment of pigeons is described in the present study. Clazuril, a benzene-acetonitrile derivative, is administered in a single dose. In laboratory studies, 121 carrier pigeons infected with E. labbeana and E. columbarum were treated once with clazuril in gelatin capsules at dose levels of 10 mg, 5 mg, 2.5 mg, 1.25 mg, 0.63 mg or with a placebo. When a single dose of 2.5 mg and higher was administered, all faecal samples became negative for oocysts within seven days after treatment. In the field studies, 1531 young and full-grown carrier pigeons, from 116 infected dove-cotes, were treated with 1 tablet of 2.5 mg clazuril. Seven days after treatment, the faecal samples of 105 dove-cotes were negative for oocysts of E. Labbeana and E. columbarum; in six dove-cotes, infection was also virtually reduced to zero. Performance in racing was not affected by treatment and side-effects were not observed.