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Applied Statistics

Faecal Egg Count Modeling

Counting the number of parasite eggs in faecal samples is a widely used diagnostic method to evaluate parasite burden. Typically a sub-sample of the diluted faeces is examined for eggs. The resulting egg counts are multiplied by a specific correction factor to estimate the mean parasite burden. To detect anthelmintic resistance, the mean parasite burden from treated and untreated animals are compared. However, this standard method has some limitations. In particular, the analysis of repeated samples may produce quite variable results as the sampling variability due to the counting technique is ignored. We propose a hierarchical model that takes this sampling variability as well as between-animal variation into account. Bayesian inference is done via Markov chain Monte Carlo sampling.

Notes: (i) The frame can be opened in a new Tab; (ii) There has been a report that the applet does not work with Internet Explorer 9. 

Rudimentary web interface

Here, we provide an alternative and very basic web interface to the R package eggCounts. Note however, that this interface only provides limited functionality. Choose according to the situation (one sample, two samples paired/unpaired) the appropriate form. 

Additional instructions on how to use the interface can be obtained here.

For intermediate and advanced use, we recommend to use the R environment to have access to the full functionality of the package eggCounts.

If you have suggestions, please send them to Reinhard Furrer.