Efficacy of toltrazuril against intestinal and hepatic coccidiosis in rabbits

The anticoccidial effect of toltrazuril (Bay Vi 9142) against Eimeria flavescens, E. intestinalis, E. magna, E. perforans and E. stiedai was tested in experimentally-infected rabbits. Continuous administration of 10-15 p.p.m. of the drug in the drinking water was highly effective in reducing oocyst output of all five species and in preventing clinical signs and macroscopic lesions. Sporulation of excreted oocysts was not affected. After 5 weeks of medication, no negative influence was noted on zootechnic performance of growing healthy rabbits. Medication of rabbits with 25 p.p.m. only during schizogony or gamogony (2 days of treatment, repeated after 5 days) quickly reduced clinical signs and oocyst output. When administered during late schizogony or gamogony, toltrazuril allowed development of immunity against reinfection with homologous species.     

Studies on an outbreak of intestinal coccidiosis in the dog

An outbreak of intestinal coccidiosis in the dog due to Isospora canis characterized by mild severe haemorrhagic diarrhoea of sudden onset, acute abdominal pain, anorexia, dehydration and relative polycythaemia is described. Although clinical recovery followed sulphonamide therapy, reinfection was common within 10 days of treatment.     

Efficacy of diclazuril in the control of intestinal coccidiosis in rabbits

The anticoccidial efficacy of diclazuril was studied in rabbits artificially infected with Eimeria flavescens, Eimeria intestinalis, Eimeria magna and Eimeria perforans. Continuous administration at 1 and 2 ppm in pelleted feed proved to be highly efficacious in controlling oocyst output and faecal scores. The weight gain was comparable and the feed efficiency slightly improved compared with the non-infected, non-medicated controls, and clinical signs were fully prevented. Medication of rabbits at 0.5 ppm also provided a significant improvement in all parameters compared with the infected, non-medicated controls. In order to obtain 100% effectiveness in the control of intestinal coccidiosis in rabbits, continuous medication at 1 ppm is recommended.     

Amprolium and furazolidone as preventive treatment for intestinal coccidiosis of piglets

Two coccidiostats, amprolium and furazolidone, were used as preventive treatments for intestinal coccidiosis in three-day-old piglets experimentally infected with 50,000 sporulated oocysts of Isospora suis.

All infected piglets, treated or not, displayed clinical signs compatible with coccidiosis. Diarrhea and anorexia appeared around five days postinoculation in the non-treated and in the amprolium-treated groups; these signs were delayed to days 7 and 8 postinoculation in the furazolidone-treated group. The treatments did not prevent growth retardation. Amprolium seemed to reduce oocyst shedding whereas furazolidone had no effect. Villous atrophy was present in all infected piglets.

     

Experimental study on the role of Brachyspira alvinipulli in intestinal spirochaetosis of geese

Ten one-day-old goslings were inoculated orally with a Brachyspira alvinipulli strain isolated from the large intestine of geese that had died of intestinal spirochaetosis (Group A), 10 day-old goslings were inoculated orally with a B. hyodysenteriae strain (Group B), and a third group of 10 goslings (Group C) served as uninfected control. The goslings were observed daily for clinical signs. They were sacrificed on days 7, 14, 21 and 35 days postinfection (PI), and necropsied. Segments of the large intestine were subjected to histopathological, immunohistochemical, electron microscopic (TEM, SEM) and microbiological examinations. Mortality did not occur during the experimental period. However, in both groups the caecum of the goslings killed by bleeding was slightly dilated, in its lumen there was a watery, yellowish and frothy content, and the mucous membrane was slightly swollen. By histopathological, immunohistochemical and electron microscopic examination, B. alvinipulli and B. hyodysenteriae could be detected in the caecum or colon, in the lumen of the glands and sometimes among the glandular epithelial cells in goslings of the respective groups, and could be reisolated from these organs by culturing. A mild inflammation of the intestinal mucosa was also noted. In transverse section of the brachyspirae, numerous (16-22) periplasmic flagella could be detected inside the outer sheath, also depending on the plane of section.     

Avian coccidiosis. A review of acquired intestinal immunity and vaccination strategies

The gut-associated lymphoid tissues contain B and T lymphocytes responsible for acquired immunity to avian coccidiosis. Intestinal B cells begin producing parasite-specific antibodies shortly after infection although their role in protecting against coccidiosis is debated. T-cell-mediated immunity, predominantly by intestinal intraepithelial lymphocytes and lamina propria lymphocytes, confers the main component of protective immunity to Eimeria. Many of these cells display the CD8 and gammadelta T-cell receptor surface antigens, phenotypic markers of cytotoxic T cells. Although their role in eliminating Eimeria infection remains to be completely elucidated, T cells have been implicated in parasite transport, and their activity is augmented by interferon-gamma and interleukin-2. Because of the importance of cell-mediated immunity, coccidiosis vaccines must be capable of stimulating intestinal T cells. Orally delivered, live parasite vaccines, either unattenuated or attenuated, are powerful stimulators of intestinal cell-mediated immunity, but antigenic variability between Eimeria species present in the vaccine and in the field may restrict their commercial application. The newer generations of recombinant DNA and subunit protein vaccines, particularly when used in conjunction with interferon-gamma and interleukin-2, have shown preliminary promise in controlling experimental infections but have yet to be commercially developed.     

Efficacy of diclazuril in the prevention and cure of intestinal and hepatic coccidiosis in rabbits

The efficacy of diclazuril against intestinal and hepatic coccidiosis was studied in artificially infected rabbits. Prophylaxis against intestinal coccidiosis was evaluated using a mixed infection of Eimeria intestinalis, Eimeria magna and Eimeria perforans. Continuous medication in the feed at 1 p.p.m. was 100% effective in reducing oocyst output and faecal scores, and weight gain and feed efficiency were normal. Hepatic coccidiosis induced by Eimeria stiedai was prevented at 0.5 and 1 p.p.m. as shown by negative oocyst counts, normal liver weight, absence of liver lesions, and normal body-weight gain and feed efficiency. Medication at 1 p.p.m. for 7 consecutive days during the prepatent phase of hepatic coccidiosis resulted in large reductions in oocyst counts and lesion scores with a normal liver weight and growth performance. Diclazuril at 1 p.p.m. in the feed prevented both intestinal and hepatic coccidiosis in rabbits and can be advocated for safe mass medication.     

朗德鹅与籽鹅、莱籽鹅杂交的产肝性能观察

随机选择朗德鹅与籽鹅、莱籽鹅的杂交鹅雏各50只,待养至4月龄后达成年体重时,每组选择20只,进行为期3～4周的填饲试验。测量填饲肥肝平均重、平均耗料量和肝料比。结果表明：朗德×菜籽鹅的平均肝重为669．00g,极显著高于朗德×籽鹅（P〈0．01）,较朗德×籽鹅、菜籽鹅与籽鹅分别提高了163．09g、289．00g和365．85g,即分别提高了32．24％、76．05％和120．68％;同时降低了单位肥肝的饲料消耗量,肝料比为1：33．71。因此,从肥肝重和耗料上综合评价得出,朗德×菜籽鹅组的填饲效果最佳,是生产肥肝最好的杂交组合。     

Immunity to sarcocystosis: Modification of intestinal coccidiosis,and disappearance of sarcocysts in dairy goats

Fifty, 2–3 month old dairy goats were each vaccinated orally with 10000 sporocysts of Sarcocystis capracanis and 25 age-matched goats served as uninoculated controls. Groups of vaccinated and control goats were challenged with lethal doses of S. capracanis at 95, 113, 205, and 274 days post-vaccination. Vaccinated goats developed subclinical sarcocystosis. Twenty-three vaccinated goats and 1 control goat died of intestinal coccidiosis and bacterial pneumonia, 15–118 days after vaccination. Myositis and degenerating sarcocysts were seen in muscles of goats necropsied at 90–186 days postvaccination. Very few, or no sarcocysts were seen in goats necropsied at 272 and 332 days post-vaccination. Vaccinated goats survived a lethal challenge inoculation indicating persistent protective immunity.