鸡的球虫病原种类调查和堆形艾美尔球虫的内生殖期虫体与组织病变研究

INVESTIGATIONS ON COCCIDIASIS IN THE DOMESTIC CHICKEN IN XIAMEN,FUJIEN,WITH SPECIAL REFERENCE TO THE LIFE CYCLE OF EIMERIA AOERVULINA AND ITS PATHOLOGY

鸡球虫病流行于世界各地,通常病鸡产生肠炎、贫血、体重和产蛋力降低,严重时大批死亡(Helen,1968),是养禽业的大敌。国外记载鸡的球虫病原有9个种(Krieger,1979)。我国广州家禽有13种球虫,其中鸡有5种球虫(佐仲贤,1981)。福建有关鸡的球虫未见报告。作者于1980—1982年在厦门地区考察了鸡球虫病原的种类及其感染状况,并对堆形艾美尔球虫的内生殖期及其组织病变进行研究。现将结果报告如下:

During 1980-1982,a survey on the species of coccidia from the domestic chicken and the life cycle of Eimeria acervulina together with its pathology were carried out in Xiamen,South Fujian.Species were distinguished in region it parasitized,average oocyst size,shape index,sporulation time, prcpatent period and pathogenicity.Nine species of Eimeria,namcly E.ten- ella,E.necatrix,E.mitis,E.brunetti,E.acervulina,E.maxima,E. praecox,E.mivati and E.adenoides and one species of Isospora,I.gallinae were identified and their morphology were studied in detail.E.adenoides is a new record from chicken in China,and the other nine species are all new records in Fujian。 The life cycle of E.acervulina consists of four asexual generations be- fore gametogony.The trophozoites,as observed in stained sections,located in the epithelial cells of villi,and most of the infection occurred in the anterior part of the small intestine.The first generation schizonts were present at the base of intestinal gland cells,and each of them contained 12-18 merozoites and one residual body.By 44 hrs,the second generation schiz- onts were found in the epithelial cells of the neck of intestinal Lieberkuhne glands.Each of them contains 12—15 merozoites.By 56 hrs,the thirdgen- eration schizonts developed at the base of villi,each schizont comprising 8 merozoites and one residual body.By 84 hrs after infection,the fourth generation schizonts were found in the base or at the tip of epithelial cells of villi,having more than 25 merozoites and a residual body within each of them.By 84—88 hrs,the macrogametocytes and mierogametocytes were mostly present along the tip or at the side of villi.The earliest time when infective oocysts were present are at 97 hrs after inoculation. It Was indicated in the present study that clinical symptoms were not detected in chickens by inoculation less than 150,000 oocysts,but the de- pression,retardation growth,anorexis and anorexia were seen by inocula- tion with more than 1,000,000 oocysts.At autopsy,characteristic discrete white transverse strand lession and white small nodules were found in the mucosa of the duodenum and proximal part of the jejunum in chicks in- oculated with 200,000 oocysts.The lession increased in number and extended further down the tract to the region of the yolk stalk as the dose was rais- ed.At the highest level of infection,the intestinal wall appeared very thin. Tissue sections revealed that the total thickness of mucosa and height of the villi in the anterior region of small intestine decreased to minimum 5 days after infection,but the length of crypt increased to maximum.In 6 days postinoculation,these changes returned to near normal.The distor- tion of epithelial cells and the loss of nuclear polarity in epithelial cells of infected chicks were also marked at 5 to 7 days after infection.The pathologic changes are closely related to the inoculation of oocyst dose. The peak of oocyst was found between 5—12 days.