Chronic Bee Paralysis : 9


Figure 2. Image of a black hairless ‘robber’ bee with nibbled wings (left) and a greasy looking bee with dislocated wings (right). Both are classic symptoms of chronic bee paralysis


comes from confirming the presence of the virus using sensitive molecular tests.


Prevalence and Transmission


Chronic bee paralysis is found on every continent where honey bees are kept. A large-scale survey completed by the NBU in 2011 suggested that CBPV was not commonly detected when random apiaries were tested – only seven in 1000 apiaries tested positive. Interestingly, the prevalence was found to be far higher when apiaries showing poor health were targeted – in this case 160 in 1000 apiaries tested positive(2)


.


All stages of the honey bee life cycle may be infected with CBPV but it is most concentrated in adult bees.


When an adult honey bee is infected, its nervous system and brain are hijacked by the virus for the purposes of viral replication, causing the characteristic trembling and paralysis. A single individual showing paralysis may harbour up to 10 trillion virus particles. The infected bee secretes the viruses from its epidermis and in its faeces, turning it into a mobilised virus factory. The hive mates of the infected bees can


September 2016 Vol 98 No 9


be infected by simply brushing up against the infected bees or through contact with faeces from contaminated individuals(1) CBPV can spread rampantly


in crowded conditions and so can be associated with large populous colonies and exacerbated by prolonged periods of confinement due to bad weather(3)


break associated with queen replacement. A recent promising


.


management method appears to be a modification of the shook swarm described by Chris Neel(5)


. The method is as follows: . CBPV is not


transmitted by varroa. As is often the case with honey bee viruses, CBPV is able to infect and replicate in other hymenopteran hosts, in this case ants(4)


. For a wonderfully


complete review of virus biology, please see the article presented by Magali Ribière(1)


. Control


Historically, chronic bee paralysis has been a very difficult disease to study because onset of symptoms can be sudden and outbreak location unpredictable. As such, there are no scientific papers that provide robust evidence to demonstrate successful treatments. Queen replacement has been suggested, but given that all races of bee appear to be susceptible, any success by this method could be attributed to a drop in adult bee population due to the brood


1 the queen is caged 2 the colony is moved at least 50 m and the bees emptied into the air (rather than onto the ground)


3 the colony is replaced in its original location and only the healthy bees return. This method probably breaks the bee-to-bee transmission route and could need to be repeated again six days later to remove previous symptomless carriers of the virus. It is early days, but some (if not all) have found this method to be helpful.


Summary


To summarise, chronic bee paralysis can be a very severe disease that is seemingly increasing in prevalence in recent years. The reasons for this increase are currently unknown, but they could be driven by more changeable weather causing confinement in populous colonies. There appears to be a clear need to extend our knowledge


Apimondia Gold Medal for Popular Beekeeping Journals, 2007, 2013 and 2015


of chronic bee paralysis and provide more useful tools for beekeepers to manage this damaging viral disease. 


References


1 Ribière, M, Olivier, V and Blanchard, P (2010). Chronic bee paralysis: a disease and a virus like no other? Journal of Invertebrate Pathology, 103, Suppl 1, S120–131.


2 Budge, GE, et al (2015). Pathogens as Predictors of Honey Bee Colony Strength in England and Wales. Plos One, 10(7), e0133228.


3 Bailey, L, et al (1983). Honey bee paralysis: Its natural spread and diminished incidence in England and Wales. Journal of Apicultural Research, 22(3), 191–195.


4 Celle, O, et al (2008). Detection of Chronic bee paralysis virus (CBPV) genome and its replicative RNA form in various hosts and possible ways of spread. Virus Research, 133, 280–284.


5 Neel, C (2016). Chronic bee paralysis virus. Bee Farmer, 2(2), 11.


The Authors


Giles Budge is science leader for bee health at Fera Science Ltd in York and a senior lecturer at Newcastle University. Kirsty Stainton is the senior bee researcher at Fera Science Ltd in York.


www.bee-craft.com


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