Long P L, Johnson J, Wyatt R D
Poult Sci. 1980 Oct;59(10):2221-4. doi: 10.3382/ps.0592221.
Chickens made partially immune to E. tenella infection exhibited cecal lesions after challenge. Some of the chickens had cecal lesions of severity similar to those of birds having their first infection with the parasite. The presence of severe cecal lesions in the partially resistant birds was not accompanied by lowered body weight gain or packed erythrocyte volumes and prothrombin time was not extended. It is suggested that there are at least three stages of immunity to E. tenella; birds may be totally resistant to parasite and no development occurs, birds may be resistant to a degree where oocysts are discharged after challenge but no lesions occur, or birds may be resistant to the clinical effects of the disease despite having severe lesions.
对柔嫩艾美耳球虫感染产生部分免疫力的鸡在受到攻击后出现盲肠病变。一些鸡的盲肠病变严重程度与首次感染该寄生虫的鸡相似。部分抗性鸡出现严重盲肠病变时，体重增加并未降低，红细胞压积和凝血酶原时间也未延长。提示对柔嫩艾美耳球虫的免疫力至少有三个阶段；鸡可能对寄生虫完全有抗性，不发生发育；鸡可能有一定抗性，受到攻击后排出卵囊但不出现病变；或者鸡尽管有严重病变，但对该病的临床影响有抗性。
