Bee Paralysis: The Common Ground of 3 Honey Bee Viruses

Thursday 19 August 2021

We are keeping our momentum with the topic of honey bee viruses and bringing you a three-for-one post this week! Bee paralysis is associated with multiple honey bee viruses, but distinction is not always made among these viruses in determining the cause of bee paralysis. Understanding the similarities and differences among these paralysis-causing viruses can help us better mitigate and manage viral infections in honey bee colonies and more fully understand the potential impacts of certain honey bee pests, varroa mites in particular.

Bee Paralysis: The Common Ground of 3 Honey Bee Viruses

Each honey bee virus is associated with its own, typically unique, set of symptoms by which it can be recognized. This type of virus identification, through observing symptoms, can be useful for some viruses that have more unique and distinct symptoms, such as deformed wing virus, but not as useful when these symptoms begin to overlap with multiple viruses. When multiple viruses have a common major symptom, it can make virus identification more difficult. This is the case for 3 of the main honey bee viruses:

  • Acute Bee Paralysis Virus (ABPV)
  • Israeli Acute Paralysis Virus (IAPV)
  • Chronic Bee Paralysis Virus (CBPV) 

Although paralysis is a recurring theme among these 3 viruses, there are important differences in impact and symptoms, transmission and vectors, and seasonality of these viruses.  All of which contribute to determining how best to manage honey bee colonies in the case of an infection.

Figure 1: Honey bees with Chronic Bee Paralysis Virus infection. Credit: The Food and Environment Research Agency (FERA), Crown Copyright

Acute Bee Paralysis Virus

The Acute Bee Paralysis Virus (ABPV) can be contracted by honey bees in all life stages, but typically in the pupal and adult life stages. This virus tends to peak in prevalence during the fall and winter months and have a lower prevalence through the spring and summer. The viral infection of ABPV can be covert, expressing no obvious signs or symptoms of disease, or overt, causing rapid death which is sometimes preceded by a state of paralysis in the infected honey bee. It has been reported that ABPV infection can inhibit the immune response in honey bees (OMAFRA, 2015).

This virus is known to be vectored through varroa mites and can also be transmitted by pollen and other food-related interactions between honey bees. Not only does the varroa mite vector the ABPV virus, it has been suggested that the digestive enzymes of varroa mites also stimulate the virus to replicate. Once infected, ABPV particles accumulate in the brain and hypopharyngeal glands of honey bees and are also easily detected in honey bee feces.

Israeli Acute Paralysis Virus

The Israeli Acute Paralysis Virus (IAPV) is closely related to ABPV, but there are key differences that set it apart. IAPV can be contracted by honey bees of all castes and of all developmental stages. The viral infection of IAPV can be asymptomatic as a covert infection, or as an overt infection can cause honey bees to have shivering wings, dark and hairless bodies, and paralysis that progresses with time and infection. This virus also compromises the infected honey bee’s immune response.

Similar to ABPV, IAPV is vectored and stimulated to replicate by varroa mites, however, in the case of IAPV the stimulus for virus replication occurs through suppressing the honey bee’s immune system defenses. In addition to transmission via varroa mites, IAPV is also transmitted through food sources.

Chronic Bee Paralysis Virus

The Chronic Bee Paralysis Virus (CBPV) can be contracted by honey bees of all castes and of all developmental stages but primarily attacks adult bees. This virus is not characterized by any particular seasonal trend of prevalence. Although the name, CBPV, suggests this virus is similar to the other bee paralysis viruses, there are important distinctions. The viral infection of CBPV can be covert and go undetected but may increase to an overt infection characterized by adult honey bees that tremble, are unable to fly, and often have dark and hairless bodies. Due to the latter symptom, this viral infection is sometimes called “hairless black syndrome”. An infected honey bee will typically die within days following the onset of infection.

Transmission of CBPV occurs topically when virus particles from one bee come into contact with the bare thorax of another bee. The CBPV symptom of hairlessness, combined with an overcrowded colony, results in the perfect conditions for CBPV transmission. Although not foodborne, CBPV is also detectable in bee feces, which may act as a source of infection through topical application to the thorax. Accumulations of virus particles can be found throughout the entire body of a CBPV infected bee but are most concentrated in the head.

It is important to recognize the similarities and differences of these viruses in order to best manage honey bee colonies in the case of an infection, and to better classify emerging honey bee viruses. For example, the emerging Lake Sinai virus strains have been determined to be most closely related to CBPV (Daughenbaugh, 2015). This relation provides a starting point from which similarities and differences can be identified between these related viruses, ultimately contributing to the betterment and increased understanding of honey bee management strategies and techniques.


Daughenbaugh, K. et al. 2015. Honey bee infecting Lake Sinai viruses, Viruses., 7(6). Available ONLINE.

OMAFRA [Ontario Ministry of Agriculture, Food and Rural Affairs] 2021. Honey bee pests and pathogens in Ontario apiaries, 2015. Food Safety and Environmental Division, Animal Health and Welfare Branch. Available ONLINE.

Pernal, S. F. and Clay, H. (eds.) 2013. Honey bee diseases and pests, 3rd Edition. Canadian Association of Professional Apiculturists, Beaverlodge, AB, Canada 68 pp.

Tantillo,G., M. Bottaro, A. Di Pinto, V. Martella, P. Di Pinto, V. Terio. 2015. Virus infections of honeybees Apis Mellifera, Italian journal of food safety., 4. Available ONLINE.

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