鹅球虫Eimeria fulva的生活史及其感染引起的组织病理变化观察

Life Cycle of Eimeria fulva and Histopathologic Changes in Infected Goslings

12只10日龄雏鹅分别接种7．0×10^5～1．5×10^6个孢子化Eimeria．fulva卵囊，在接种后24～264h分期扑杀．对E．fulva的生活史及其感染引起的组织病理变化进行了动态性观察。在内生性发育过程中，E．fulva至少有2个世代的裂殖生殖阶段，每个成熟的裂殖体含15个左右的裂殖子。接种后168h左右，虫体进入配子生殖阶段。感染后7．5d始有卵囊排出，显露期为2．5d。25C下卵囊孢子化时间为60～84h。E．fulva可寄生于整个肠道和泄殖腔的绒毛上皮、肠腺和固有膜中，引起上皮坏死、脱落以及肠壁水肿、出血和炎性细胞浸润等。病变以空肠和回肠较为严重。感染鹅严重腹泻，但不会发生死亡。研究结果表明，E．fulva对雏鹅具有中等程度的致病性。

Twelve 10-day-old artifieially：reared eoeeidia-free goslings were inoculated orally with 7.0 ×10^5-1.5 × 10^6 sporulated oocysts of Eimeria fulva ,respectively,and killed at intervals from 24 h to 264 h after inoculations. The life cycle of E. fulva and histopathologic changes of its infection were observed chronologically. The results showed that at least 2 generations of meronts developed in the endogenous stage of the life cycle of E. fulva. Each meront contained about 15 merozoites. Development of gametes began at about 168 halter infection. The prepatent period was 7.5 d and the discharge of oocysts continued for 2.5 d. Sporulation of oocysts occurred in 60-84 h at 25 C. Developmental stages were present in the epithelial cells of villi and crypts and in lamina propria of the whole intestine and cloaca,resulting in desquamation and necrosis of the epithelium（including crypt epithelium）,edema ,hemorrhages ,infiltration of inflammatory cells and villous atrophy. Histological lesions were pronounced in the jejunum and the ileum during the periods of gamogony and oocyst shedding. The infected goslings mainly showed severe diarrhoea but no deaths. The results suggest that E. fulva may be mildly pathogenic for goslings.