| In order to study the prevalence and identify species of the rabbits coccidian, a survey about housing robbits coccidiosis was performed in Henan province from October 2007 to June 2008. The result showed the infection rate of coccidium was very high in all areas that we investigated. The infection rate of the farm was 100%(8/8), and average infection rate of rabbits was 64.59%. Infection rate of coccidian in pre-wean,1-3-month,4-6-month,7-12-month, more than 1 year respectively was 67.1%,76.0%,59.8%,65.2%,49.1%.12 species of the Eimeria were identified, namely, E. exigua, E. elongate, E. coecicola, E. stiedai, E. intestinalis, E. piriformis, E. neoleporis, E. flavescens, E. perforans, E. irresidua, E. media, E. magna. Moreover, E. perforans, E. elongate, E. intestinalis and E. stiedai were the predominant species. There were difference of infective intensity in different ages and in different areas.A total of 22 coccidia-free rabbits inoculated with varying numbers of oocysts was examined for endogenous stages. Take two coccidian-free rabbits as control. The tissue section results showed there were 5 asexual and 1 sexual generations in a conventional life cycle. According to the shape and the number of merozoites in a meront, maybe two types meront existed in each of asexual generation. Type A gave rise to a smaller number of thick polynucleate merozoites, while in the type B meronts slender uninucleate merozoites.Mature first-generation schizonts together with large multinucleate trophozoites were first seen between 60 and 72 h after inoculation. They occupied epithelial cells of the glands in the jejunum. Type A meront contains 2-4 schizonts, measuring 4.7μm×2.1μm, and type B meront contains 8-18 schizonts, measuring 11.1μm×1.5μm.Mature second-generation schizonts were seen at 84 h throughout the caecum and colon, situated the gland epithelial cells. Type A contains 2-4 schizonts, measuring5.3μm×1.8μm, and type B meront contains 12-36 schizonts, measuring 10.3×1.7pm.These were third-generation schizonts which, when mature between 96 to 120 h. They were observed in the epithelial cells of the caecum and colon villus. Type A contains 2-4 schizonts, measuring5.1μm×1.6μm, and type B meront contains 9-16 schizonts, measuring 10μm×1.4μm.Fourth-generation schizonts developed in the base of the glands of the caceum and colon. Type A contains 2-4 schizonts, measuring4.2μm×1.4μm, and type B meront contains 12-36 schizonts, measuring 7.5μm×1.2μm.Young gamonts were first observed in the glandular epithelium of the caeceum and colon at 167 h after inoculation. A macrogametocyte gave arise a macrogamete, but a microgametocyte contained lots of microgametes. Oocysts were found in villus and glandular epithelium of the caeceum and colon at 201 h after inoculation.Pathological changes of the jejunum were not observed until 60 h after inoculation. With the development of the coccidium, evident pathological changes of caeceum and colon were found at 120 h after inoculation, epithelia degeneration and necrosis, inflammatory cell infiltrate in lamina propria. eosinophilic granulocyte infiltrate was observed in the caeceum and procussus vermiformis. |
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