Modelling methods to improve our understanding of chronic bee paralysis in the European honey Bee (Apis mellifera)

Abstract

Chronic bee paralysis virus (CBPV) is the causative agent of chronic bee paralysis (CBP) and is an emerging virus in Western honey bees (Apis mellifera). Due to its emergent nature, CBP is relatively poorly understood, and there are several knowledge gaps that, if filled, would significantly enhance our ability to predict and control CBP outbreaks. This study sought to fill some of those gaps by identifying CBP drivers, learning more about its epidemiology, and investigating potential mitigation techniques. Identifying the possible drivers of disease is essential when attempting to understand a new disease. National Bee Unit inspection data and Met Office weather records were combined and analysed to determine if the weather had any effect on the risk of six honey bee diseases (Europen foulbrood (EFB), American foulbrood (AFB), CBP, varroosis, chalkbrood and sacbrood) to colonies. The effect of the weather variables on the risk of the different diseases depended heavily on the disease. For example, EFB and varroosis were significantly impacted by weather compared to CBP and AFB, which were not. A laboratory-based method was used to examine the transmission rate and latent period of CBP. Through an observational experiment and RT-qPCR on bees exposed to CBP, data was gathered on the impact of exposure time on CBP transmission and latency. Finally, an individual-based model was used to examine two questions: how climate change might affect honey bee colony size and how effective three CBP management techniques are in controlling CBP spread within a colony. The simulated honey bee colonies might be significantly weaker when exposed to the 2061 rainfall weather projections, while the projected temperatures had almost no effect. Simulated colonies with CBP were weaker than healthy ones, and the mitigation technique that demonstrated improved control in simulations was the isolation of newly emerged bees.