The causes and consequences of non-normal distributions in parasitology

Most distributions in biology are well described by a normal distribution and Fisher provided a convincing explanation for this. However, this is not the case in parasitology. Usually parasites followed a skewed distribution that is empirically described by a negative binomial distribution. Similarly, the components of the protective immune response (IgA, IgE, eosinophils and mast cells) follow skewed distributions. The causes of these non-normal distributions will be discussed and the consequences, both biological and statistical, described.