What Is Chronic Bee Paralysis Virus?

A beekeeper inspecting for diseases like Chronic Bee Paralysis Virus

Chronic bee paralysis virus (CBPV) is a highly infectious viral disease that affects adult honey bees (Apis mellifera). Sick bees experience chronic paralysis towards the end of the infection and typically die within one week of contraction.

CBPV is an emerging viral disease that plays a role in the sudden collapse of honeybee colonies (Colony Collapse Disorder).

What are the symptoms of Chronic bee paralysis virus?

Honey bees show no signs of CBPV virus in the first five days, making early detection challenging for beekeepers. The late stages of the virus will display a range of symptoms that present in two ways:

Type 1 infection: The more common, resulting in bees with weak, trembling wings and a bloated abdomen. Look for bee clusters and crawling bees at the hive’s entrance. You may also notice signs of dysentery.

Type 2 infection: A less common type causing bees to have a greasy, black appearance and abdominal hair loss. Adults may have the capacity to fly until their death.

Sometimes, the infected insect will be asymptomatic while still spreading the disease.

How does CBPV affect the hive?

A hive may function normally with low levels of CBPV. However, if left untreated, an outbreak may cause colony collapse. Like most viral diseases, it can overrun a stressed colony. It may also co-exist with other viruses.

Additional reading on bee viruses:


Beekeepers can help prevent CBPV and similar honey bee viruses by maintaining healthy colonies.

Requeen the hive: Some bee stocks exhibit better hygienic behavior, which increases resistance to diseases and pests. The Russian bee breed instinctively suppresses varroa mite populations, often reducing viral spread.

Keep bees nourished: During food shortages, provide sugar syrup or pollen substitutes to keep the hive healthy.

Reduce chemicals: Restrict hive treatments like miticides, which may reduce bee virus tolerance.

Control varroa mites: The Varroa destructor is an effective vector of CBPV in honey bees. Implement treatment if mite levels exceed 3 per 100 bees. Learn more about eradicating varroa mites here.

Reduce stress: Stress impacts a colony’s ability to fight off illness. Beekeepers should skip unnecessary inspections and avoid opening hives in cold weather.

Hygienic beekeeping practices: Maintain clean hive tools and equipment to reduce spread; never move frames from sick to healthy ones or reuse equipment from dead hives; space out hives to reduce drifting behavior.

Keep a watchful eye on other bee threats.

How do I treat CBPV?

There are currently no reliable treatments for chronic bee paralysis virus. Existing options for killing the infection may also harm or kill the bees.

Beekeepers can help control the disease with supplemental feeding and requeening. The prognosis is good for colonies diagnosed early. Following recommended beekeeping practices and implementing sanitary measures will greatly help the colony. Source.

Disease transmission

Chronic bee paralysis virus is transmitted by ingesting infected food sources and bee feces. Viral transfer also occurs when bees contact each other in the hive. The virus is transferred between hives when infected bees rob, drift, or swarm.

7 facts about chronic bee paralysis virus

  1. The virus is distributed globally, with increasing cases in North America, Asia, and Europe.
  2. CBPV can infect thriving colonies, resulting in thousands of dead bees outside the hive.
  3. Bees develop bloated abdomens due to a honey sac that fills with fluid.
  4. CBPV is an unclassified bipartite RNA virus19. It was first characterized in 1963.
  5. Crowded bee colonies are especially susceptible to the virus in spring and summer.
  6. Other names for the paralysis include little blacks and hairless black syndrome.
  7. The first two honey bee viruses isolated by scientists were chronic bee paralysis virus and acute bee paralysis virus.

Commonly asked questions

Does CBPV affect other insects?

CBPV mainly uses the honey bee as a host. It also replicates on the Formica rufa and Camponotus vagus, two species of predatory ants.

What diseases are similar to CBPV?

Chronic bee paralysis virus is a similar infection to acute bee paralysis virus and slow bee paralysis virus. They all have similar symptoms and modes of transmission and are fatal for bees due to paralysis.

To learn more about honey bee diseases, check out our resources on Sacbrood disease and Nosema disease.

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