使用改良加藤厚涂片法比较个体粪便样本和混合粪便样本以评估曼氏血吸虫及土源性蠕虫感染强度
Comparison of individual and pooled stool samples for the assessment of intensity of Schistosoma mansoni and soil-transmitted helminth infections using the Kato-Katz technique.
作者信息
Kure Ashenafi, Mekonnen Zeleke, Dana Daniel, Bajiro Mitiku, Ayana Mio, Vercruysse Jozef, Levecke Bruno
机构信息
Public Health Laboratory, Southern Nations Nationalities and People's Regional State Health Bureau, Hawassa, Ethiopia.
Department of Medical Laboratory Sciences and Pathology, Jimma University, Jimma, Ethiopia.
出版信息
Parasit Vectors. 2015 Sep 24;8:489. doi: 10.1186/s13071-015-1101-1.
BACKGROUND
Our group has recently provided a proof-of-principle for the examination of pooled stool samples using McMaster technique as a strategy for the rapid assessment of intensity of soil-transmitted helminth infections (STH, Ascaris lumbricoides, Trichuris trichiura and hookworm). In the present study we evaluated this pooling strategy for the assessment of intensity of both STH and Schistosoma mansoni infections using the Kato-Katz technique.
METHODS
A cross-sectional survey was conducted in 360 children aged 5-18 years from six schools in Jimma Zone (southwest Ethiopia). We performed faecal egg counts (FECs) in both individual and pooled samples (pools sizes of 5, 10 and 20) to estimate the number of eggs per gram of stool (EPG) using the Kato-Katz technique. We also assessed the time to screen both individual and pooled samples.
RESULTS
Except for hookworms, there was a significant correlation (correlation coefficient = 0.53-0.95) between the mean of individual FECs and the FECs of pooled samples for A. lumbricoides, T. trichiura and S. mansoni, regardless of the pool size. Mean FEC were 2,596 EPG, 125 EPG, 47 EPG, and 41 EPG for A. lumbricoides, T. trichiura, S. mansoni and hookworm, respectively. There was no significant difference in FECs between the examination of individual and pooled stool samples, except for hookworms. For this STH, pools of 10 resulted in a significant underestimation of infection intensity. The total time to obtain individual FECs was 65 h 5 min. For pooled FECs, this was 19 h 12 min for pools of 5, 14 h 39 min for pools of 10 and 12 h 42 min for pools of 20.
CONCLUSIONS
The results indicate that pooling of stool sample holds also promise as a rapid assessment of infections intensity for STH and S. mansoni using the Kato-Katz technique. In this setting, the time in the laboratory was reduced by 70 % when pools of 5 instead of individual stool samples were screened.
背景
我们的团队最近提供了一项原理验证，即使用麦克马斯特技术检测混合粪便样本，以此作为快速评估土壤传播的蠕虫感染（STH，蛔虫、鞭虫和钩虫）强度的策略。在本研究中，我们使用加藤厚涂片法评估了这种混合策略用于评估STH和曼氏血吸虫感染强度的效果。
方法
在埃塞俄比亚西南部吉马地区的六所学校对360名5至18岁的儿童进行了横断面调查。我们使用加藤厚涂片法对个体样本和混合样本（混合样本量分别为5、10和20）进行粪便虫卵计数（FEC），以估计每克粪便中的虫卵数（EPG）。我们还评估了筛查个体样本和混合样本所需的时间。
结果
除钩虫外，无论混合样本量大小，蛔虫、鞭虫和曼氏血吸虫的个体FEC平均值与混合样本的FEC之间均存在显著相关性（相关系数=0.53-0.95）。蛔虫、鞭虫、曼氏血吸虫和钩虫的平均FEC分别为2596 EPG、125 EPG、47 EPG和41 EPG。除钩虫外，个体粪便样本检查和混合粪便样本检查的FEC没有显著差异。对于这种STH，10个样本的混合会导致感染强度的显著低估。获得个体FEC的总时间为65小时5分钟。对于混合FEC，5个样本的混合为19小时12分钟，10个样本的混合为14小时39分钟，20个样本的混合为12小时42分钟。
结论
结果表明，使用加藤厚涂片法，粪便样本混合也有望作为快速评估STH和曼氏血吸虫感染强度的方法。在这种情况下，当筛查5个样本的混合而非个体粪便样本时，实验室时间减少了70%。
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