Honeybee Diseases - Chronic Bee Paralysis Virus

Chronic Bee Paralysis is a disease of adult honeybees caused by the chronic bee paralysis virus. It is very contagious, progresses at speed, and leads to paralysis and death in adult bees. It can infect strong and weak colonies alike resulting in thousands of dead bees on the floor and at the entrance of the hive.

Recognition

Video Courtesy The National Bee Unit, © Crown Copyright

Maggie Gill from the The National Bee Unit demonstrates how to diagnose CBPV in the hive. Symptoms are easily recognised.

There are two forms of the disease currently described. The first manifests as abnormal trembling of the body and wings. Affected bees are not able to fly, and crawl on the ground eventually dying in or in front of the colony. Bloated abdomens may also be observed due to distension of the honey sac, and may be seen huddled together on top of the bee cluster. The second form is manifested by the hairless‑black syndrome, when adult bees can look very black and shiny as their body hairs (and wings) are nibbled off by healthy bees trying to remove them from the colony. Death occurs around a week from infection.

CBPV symptoms can easily be confused with poisoning as both attack the nervous system of the bees leading to involuntary movements, trembling and shaking. The key difference is that poisoning leads to dead bees all around the hives and apiary, whereas CBPV leads to dead and dying bees inside the hive and at the entrance. Bees observed spinning on their backs as they attempt to fly are associated with poisoning and not CBPV.

Detection

Apiary / Hive Inspection - Due to the conspicuous nature of CBPV symptoms and the resulting deaths, routine inspection of the apiary and hives will reveal its presence.

Monitoring - As with all honeybee related diseases vigilance is important. Regular, careful and thorough inspections will reveal incidence of CBPV in the apiary.

Treatment

There is no chemical treatment for CBPV at present. The virus is transmitted through physical contact and by ingestion of contaminated food and when healthy bees nibble the body hairs and wings of infected bees. Stronger colonies will suffer more through increased physical contact. To reduce the transmission increase space within infected hives by adding supers and more brood boxes. Follow best practice with colony proximity to reduce robbing and inter-colony transmission. Consider replacing queens that produce bees which are more susceptible.

Please download the CBPV Info Sheet and the Integrated Pest Management plan to obtain a printable version of CBPV information, detection and management methods

Vectors

Physical Contact - Infected adult bees will carry the virus wherever they go, and move from hive to hive, transferring to other bees and colonies.

• Robbing - An infected colony will weaken and become a target for robbers. Not only do they take contaminated stores but also pick up the virus through physical contact with infected bees.
• Drifting - Poor apiary design and location will allow young bees to drift into neighbouring colonies. This is particularly important with drones as are they are accepted into any colony.
• Bee Migration - Bees from collapsing colonies abscond from their own hive with the robbers and increase the transmission of the virus to other colonies.
• Migratory Beekeeping - Moving colonies around the countryside to exploit nectar flows such as heather moors and seasonal OSR has great potential to rapidly spread all diseases. Colony health should be checked before deciding if it is safe to move them.
• Swarming - A swarm from an infested colony will always carry the virus with it. It is essential to monitor any swarm for CBPV and other diseases and treat it before introducing it to the apiary.
• Feral Swarms - Swarms from feral colonies are no more likely to be free than those from managed colonies but can spread the virus naturally by 3-5km per year.
• Beekeepers - Careless manipulative management by the beekeeper can transfer affected bees to other colonies in the apiary and to other apiaries. Migratory beekeeping can cause a rapid spread throughout the countryside.

Try the Honeybee Diseases Quiz

About the 'My Beekeeping Kit' website.

Contact Iain Dewar for enquiries, suggestions, corrections and contributions for improving the notes. Always welcome!