Nationwide Screening for Bee Viruses and Parasites in Belgian Honey Bees.

Severine Matthijs,Paul De Winter,Claude Saegerman,Marleen Brunain,Nick De Regge,Valerie Vandenberge,Jacqueline Evers,Bénédicte Verhoeven,Stefan Roels,Valérie De Waele,Dirk De Graaf

doi:10.3390/v12080890

Abstract

The health of honey bees is threatened by multiple factors, including viruses and parasites. We screened 557 honey bee (Apis mellifera) colonies from 155 beekeepers distributed all over Belgium to determine the prevalence of seven widespread viruses and two parasites (Varroa sp. and Nosema sp.). Deformed wing virus B (DWV-B), black queen cell virus (BQCV), and sacbrood virus (SBV) were highly prevalent and detected by real-time RT-PCR in more than 95% of the colonies. Acute bee paralysis virus (ABPV), chronic bee paralysis virus (CBPV) and deformed wing virus A (DWV-A) were prevalent to a lower extent (between 18 and 29%). Most viruses were only present at low or moderate viral loads. Nevertheless, about 50% of the colonies harbored at least one virus at high viral load (>107 genome copies/bee). Varroa mites and Nosema sp. were found in 81.5% and 59.7% of the honey bee colonies, respectively, and all Nosema were identified as Nosema ceranae by real time PCR. Interestingly, we found a significant correlation between the number of Varroa mites and DWV-B viral load. To determine the combined effect of these and other factors on honey bee health in Belgium, a follow up of colonies over multiple years is necessary.

Highlights

The ecological and economic importance of honey bees is well established
KBV was not detected in any of our samples, while Acute bee paralysis virus (ABPV), chronic bee paralysis virus (CBPV) and deformed wing virus A (DWV-A) were found with a low prevalence
Three viruses were found with a high prevalence: black queen cell virus (BQCV) and sacbrood virus (SBV) were present in more than 95% of the analyzed honey bees, while Deformed wing virus B (DWV-B)

Summary

Introduction

The ecological and economic importance of honey bees is well established. Honey bees are highly valuable pollinators for both wild flowering plants and economically important crops. Honey bees and other pollinators face multiple threats, including viruses, parasites, bacteria, pesticides and lack of sufficient or high-quality food. The loss of managed colonies of the western honey bee Apis mellifera has prompted researchers to study the drivers of colony mortality [1,2,3,4,5]. Viruses are considered to be among the key players of honey bee declines [6,7,8,9,10]. Several of the most common honey bee viruses (deformed wing virus complex, black queen cell virus, sacbrood virus and the acute bee paralysis complex) have been found on all continents [11]

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