Shirley M W, Bellatti M A, Millard B J
Parasitology. 1982 Apr;84(Pt 2):215-26. doi: 10.1017/s0031182000044784.
An egg-adapted line of Eimeria necatrix has now been passaged 40 times in the chorio-allantoic membranes of embryonated eggs. Between the 21st and 40th passage in eggs the parasite was subjected to a selection for precocious development, and its pre-patent period in this host is now 123-125 h. The parasite continued to adapt to the chorio-allantoic membrane throughout the period of the passages and its development in this tissue caused the growth of the host embryo to be markedly stunted. In chickens, both the reproduction and the pathogenicity of the egg-adapted line decreased with increasing numbers of passages in eggs. A comparison of the immunogenicity of the egg-adapted line and its parent strain in chickens kept on litter, showed that substantially more oocysts of the egg-adapted line had to be given to induce complete protection.
一种致弱的柔嫩艾美耳球虫株现已在鸡胚的绒毛尿囊膜上传代40次。在第21代至第40代鸡胚传代过程中，对该寄生虫进行了早熟发育选择，其在该宿主中的潜隐期现为123 - 125小时。在整个传代期间，该寄生虫持续适应绒毛尿囊膜，其在该组织中的发育导致宿主胚胎生长明显受阻。在鸡中，致弱株的繁殖力和致病性均随鸡胚传代次数的增加而降低。对垫料饲养的鸡中致弱株及其亲代菌株的免疫原性进行比较，结果显示，必须给予更多的致弱株卵囊才能诱导出完全保护。
