4. Sampling

Methods can be grouped into those looking to confirm the presence of the disease by testing an individual symptomatic larva for M. plutonius, and those that hope to confirm the presence of M. plutonius in asymptomatic material, such as in bulk samples of adult bees or disease-free colonies in proximity to disease. When considering the latter, it is important to consider the within-hive distribution of the pathogen and also how the sample size may affect the power of the subsequent test. For example, when assuming a hive population of 50,000 individuals, sampling 5 adult bees provides a 95 % confidence of detecting a pathogen with a minimum prevalence of 50 %, whereas sampling 60 adult bees increases the power of the testing regime to enable a more meaningful minimum pathogen detection of 5 % prevalence. No single study has provided the necessary detail to make definitive recommendations on sample location and size, therefore this chapter concentrates on summarizing the sampling methods and knowledge to date (see also de Graaf et al., 2013; Human et al., 2013). Storage temperature is not crucial. All sample types can be refrigerated for several hours and stored at -20º C for longer periods.