Current W L, Upton S J, Haynes T B
J Protozool. 1986 May;33(2):289-96. doi: 10.1111/j.1550-7408.1986.tb05608.x.
The life cycle and morphology of a previously undescribed species of Cryptosporidium isolated from commercial broiler chickens is described. The prepatent period for Cryptosporidium baileyi n. sp. was three days post oral inoculation (PI) of oocysts, and the patent period was days 4-24 PI for chickens inoculated at two days of age and days 4-14 for chickens inoculated at one and six months of age. During the first three days PI, most developmental stages of C. baileyi were found in the microvillous region of enterocytes of the ileum and large intestine. By day 4 PI, most parasites occurred in enterocytes of the cloaca and bursa of Fabricius (BF). Mature Type I meronts with eight merozoites first appeared 12 h PI and measured 5.0 x 4.9 micrometers. Mature Type II meronts with four merozoites and a large granular residuum first appeared 48 h PI and measured 5.1 x 5.1 micrometers. Type III meronts with eight short merozoites and a large homogeneous residuum first appeared 72 h PI and measured 5.2 x 5.1 micrometers. Microgamonts (4.0 x 4.0 micrometers) produced approximately 16 microgametes that penetrated into macrogametes (4.7 x 4.7 micrometers). Macrogametes gave rise to two types of oocysts that sporulated within the host cells. Most were thick-walled oocysts (6.3 x 5.2 micrometers), the resistant forms that passed unaltered in the feces. Some were thin-walled oocysts whose wall (membrane) readily ruptured upon release from the host cell. Sporozoites from thin-walled oocysts were observed penetrating enterocytes in mucosal smears. The presence of thin-walled, autoinfective oocysts and the recycling of Type I meronts may explain why chickens develop heavy intestinal infections lasting up to 21 days. Oocysts of C. baileyi were inoculated orally into several animals to determine its host specificity. Cryptosporidium baileyi did not produce infections in suckling mice and goats or in two-day-old or two-week-old quail. One of six 10-day-old turkeys had small numbers of asexual stages only in the BF. Four of six one-day-old turkeys developed mild infections only in the BF, and sexual stages of the parasite were observed in only one of the four. All seven one-day-old ducks and seven two-day-old geese developed heavy infections only in the BF with all known developmental stages present.
描述了从商品肉鸡中分离出的一种此前未描述过的隐孢子虫物种的生命周期和形态。贝利隐孢子虫新种的潜隐期为经口接种卵囊后3天，对于2日龄接种的鸡，排虫期为接种后4 - 24天，对于1月龄和6月龄接种的鸡，排虫期为接种后4 - 14天。在接种后的前3天，贝利隐孢子虫的大多数发育阶段见于回肠和大肠肠上皮细胞的微绒毛区域。到接种后第4天，大多数寄生虫见于泄殖腔和法氏囊的肠上皮细胞。含8个裂殖子的成熟I型裂殖体在接种后12小时首次出现，大小为5.0×4.9微米。含4个裂殖子和一个大颗粒状残体的成熟II型裂殖体在接种后48小时首次出现，大小为5.1×5.1微米。含8个短裂殖子和一个大均质残体的III型裂殖体在接种后72小时首次出现，大小为5.2×5.1微米。小配子体（4.0×4.0微米）产生约16个小配子，小配子侵入大配子（4.7×4.7微米）。大配子产生两种类型的卵囊，它们在宿主细胞内形成孢子。大多数是厚壁卵囊（6.3×5.2微米），是在粪便中未改变通过的抗性形式。有些是薄壁卵囊，其壁（膜）在从宿主细胞释放时容易破裂。在黏膜涂片中观察到薄壁卵囊的子孢子侵入肠上皮细胞。薄壁、自身感染性卵囊的存在以及I型裂殖体的循环可能解释了为什么鸡会发生持续长达21天的严重肠道感染。将贝利隐孢子虫的卵囊经口接种到几只动物中以确定其宿主特异性。贝利隐孢子虫在乳鼠、山羊或2日龄或2周龄鹌鹑中未引起感染。6只10日龄火鸡中有1只仅在法氏囊中出现少量无性阶段。6只1日龄火鸡中有4只仅在法氏囊中出现轻度感染，且仅在其中1只中观察到寄生虫的有性阶段。所有7只1日龄鸭和7只2日龄鹅仅在法氏囊中出现严重感染且存在所有已知发育阶段。
