The contribution of simple random sampling to observed variations in faecal egg counts.
The contribution of simple random sampling to observed variations in faecal egg counts.
复制标题
简单随机抽样对观察到的粪便卵数变化的贡献。
DOI：
10.1016/j.vetpar.2012.03.043
复制
发表时间：
2012
影响因子：
2.6
通讯作者：
F. Lewis
中科院分区：
文献类型：
--
作者：
P. Torgerson;M. Paul;F. Lewis
自1907年戈塞特以笔名“学生”发表经典论文证明悬浮在液体中并用血球计测量的酵母细胞符合泊松过程以来，已经过去了100多年。类似地，粪便悬浮液中的寄生虫卵也符合泊松过程。尽管如此，对于如何分析或解释麦克马斯特或类似的定量寄生虫诊断技术的观察结果仍存在常见的误解，这些技术广泛用于评估粪便中的寄生虫卵。麦克马斯特技术可以很容易地从理论角度证明它给出的可变结果不可避免地是由于寄生虫卵在充分混合的粪便样本中的随机分布而产生的。描述了导致这种变异性的泊松过程，并举例说明了观察到的粪便卵数可能产生的潜在大置信区间，这些粪便卵数是根据麦克马斯特载玻片上的观察结果计算得出的。尝试修改麦克马斯特技术或其他定量技术以确保均匀的鸡蛋计数注定会失败，并且掩盖了对泊松过程的无知。提供了一种从重复计数中立即识别过度变异/不良采样的简单方法。
It has been over 100 years since the classical paper published by Gosset in 1907, under the pseudonym “Student”, demonstrated that yeast cells suspended in a fluid and measured by a haemocytometer conformed to a Poisson process. Similarly parasite eggs in a faecal suspension also conform to a Poisson process. Despite this there are common misconceptions how to analyse or interpret observations from the McMaster or similar quantitative parasitic diagnostic techniques, widely used for evaluating parasite eggs in faeces. The McMaster technique can easily be shown from a theoretical perspective to give variable results that inevitably arise from the random distribution of parasite eggs in a well mixed faecal sample. The Poisson processes that lead to this variability are described and illustrative examples of the potentially large confidence intervals that can arise from observed faecal eggs counts that are calculated from the observations on a McMaster slide. Attempts to modify the McMaster technique, or indeed other quantitative techniques, to ensure uniform egg counts are doomed to failure and belie ignorance of Poisson processes. A simple method to immediately identify excess variation/poor sampling from replicate counts is provided.