Welch R D, Smith P H, Malone J B, Holmes R A, Geaghan J P
Am J Vet Res. 1987 Mar;48(3):345-7.
An enzyme-linked immunosorbent assay (ELISA) was evaluated as a method of determining relative immunoconversion rates in calves and how immunoconversion rates and strength of optical density values correlate with prevalence of Fasciola hepatica fecal egg shedding. Ten to 55 calves and cows were examined from each of 10 separate beef cattle herds in central and southern Louisiana. Infection prevalence rates for calves averaged 8% higher when ELISA optical density values were used than those when fecal egg count data were used. Of 55 calves in 8 herds that were ELISA positive, 39 were shedding F hepatica eggs; of 53 calves that were shedding eggs, 14 were ELISA negative. Significant correlation of calf fecal and ELISA prevalence was observed for 8 herds by linear regression analysis. A chi 2 analysis showed that calf ELISA and fecal egg shedding data were not independent. Results indicate that positive ELISA reactions for as few as 10 to 15 calves from the fall calf crop of a given herd are sufficiently accurate to be used to assess F hepatica herd infection rates, the likelihood of liver condemnations at feedlot destinations, and variation between individual farms in fascioliasis infection risk. The test was less valuable as a diagnostic test when used in adult animals previously exposed to F hepatica or on an individual animal basis.
对酶联免疫吸附测定（ELISA）作为一种确定犊牛相对免疫转化率的方法，以及免疫转化率和光密度值强度与肝片吸虫粪便虫卵排出率之间的相关性进行了评估。从路易斯安那州中部和南部的10个不同肉牛群中，分别检查了10至55头犊牛和母牛。当使用ELISA光密度值时，犊牛的感染率平均比使用粪便虫卵计数数据时高8%。在8个ELISA呈阳性的牛群中的55头犊牛中，39头排出肝片吸虫卵；在53头排出虫卵的犊牛中，14头ELISA呈阴性。通过线性回归分析，观察到8个牛群中犊牛粪便和ELISA患病率之间存在显著相关性。卡方分析表明，犊牛ELISA和粪便虫卵排出数据并非相互独立。结果表明，对于给定牛群秋季犊牛群中少至10至15头犊牛的阳性ELISA反应，其准确性足以用于评估肝片吸虫牛群感染率、育肥场目的地肝脏被判不合格的可能性以及各农场之间肝片吸虫病感染风险的差异。当用于先前接触过肝片吸虫的成年动物或个体动物时，该检测作为诊断检测的价值较低。
