Slow bee paralysis virus

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Slow bee paralysis virus
Virus classification Red Pencil Icon.png
(unranked): Virus
Realm: Riboviria
Kingdom: Orthornavirae
Phylum: Pisuviricota
Class: Pisoniviricetes
Order: Picornavirales
Family: Iflaviridae
Genus: Iflavirus
Species:
Slow bee paralysis virus
The virus infects bees through mites that lives in their colonies. Honeybee polen.JPG
The virus infects bees through mites that lives in their colonies.

Slow bee paralysis virus (SBPV) is a virus discovered in England in 1974 [1] that infects honeybees (Apis mellifera), bumblebees [2] (Bombis spp.), and silkworms (Bombyx mori) through Varroa destructor mite infestations. The virus causes paralysis in the front two pairs of legs of adult bees eventually killing its hosts. The virus is in the iflaviridae family of viruses. Infection by iflaviridae viruses is among the leading cause of death of honeybee colonies. [3] As bees and silkworms are of great economic and biological importance, the virus is the subject of ongoing research.

Contents

Structure

Structure of slow bee paralysis virus (SBPV) virion and the icosahedral asymmetric unit. JVI.00680-16 F1.large.jpg
Structure of slow bee paralysis virus (SBPV) virion and the icosahedral asymmetric unit.

The virus has an "... icosahedral capsid formed from sixty copies of three proteins which are common to picornaviruses." [4] These proteins are 46, 27, and 29 kilodaltons. [5] One of these three proteins (VP3) has a C-terminal globular domain which folds to create a single globular protein P domain. [3] The position of this protruding protein is such that it may easily encounter and interact with the bee host cells. Because of this, it is believed the protruding protein may act as a receptor. This receptor activity has been known to occur in many plant viruses, but has not yet been seen in this order. [4]

Genome

SBPV is a non-enveloped Positive-sense single-stranded RNA virus, and is 9470 nucleotides long. [6] The virus has approximately 300 nucleotides of 5' untranslated region and approximately 270 nucleotides of 3' untranslated region and is terminated by a poly(A) tail. [5] The RNA has a coding region which codes for RNA-dependent RNA polymerase. Though it was not identified, it is expected that a viral genome-linked protein, involved in stability, replication, and translation, would be bound to the 5' end. [5] There are two strains of the virus, named "Rothamsted" and "Harpenden" which are 83% identical at the nucleotide level, and 94% identical at the amino acid level. [5]

Replication cycle

Entry

Though little is known about the genome release mechanism, it has been hypothesized that low pH may promotes SBPV genome release, and the virus may enter host cells through endosomes. [7] This would suggest that the virus effectively circumvents the host cells' cap-dependent translation. [5] Furthermore, it has been previously shown that picornaviruses enter the host cell membrane through the use of liposomes, however, SBPV is not myristoylated. It is possible, then, that SBPV enters the cell membrane through "...residues 4–21 of VP4 of SBPV [which] form an amphipathic α-helix in which the polar and hydrophobic residues are segregated to the opposite sides." [7] On the other hand, it is not clear if VP4 contributes to virus cell entry at all, since the electron density of VP4 could not be identified in the slow bee paralysis virus. [3] [7]

Transmission, infection, and diagnosis

Varroa destructor on honeybee host Varroa destructor on honeybee host.jpg
Varroa destructor on honeybee host

SBPV is transmitted by the common honeybee parasite, the Varroa destructor mite. It is transmitted directly to adults and pupae when the mite feeds upon and infects the bee's hemolymph. [2] The virus accumulates mainly in the head, salivary glands, and fatty tissues of the bee; it accumulates to a much lesser degree in the hindlegs, midgut, and rectum. [8] Because of this, the virus may also be spread through oral transmission between bees.

Many viruses that plague bees are found living within the Varroa mite, and many, like SBPV, can be directly transmitted to the bee by the mites themselves. [9] As the name suggests, slow bee paralysis virus induces paralysis to the anterior legs ten to twelve days after infection.

Management

The virus has a low natural prevalence across large parts of Europe, but can be propagated in bee colonies with varying levels of Varroa infestations. [5]

Management of SBPV can be effectively achieved through management of the Varroa destructor mite. Management strategies include:

Related Research Articles

Coxsackie B4 virus are enteroviruses that belong to the Picornaviridae family. These viruses can be found worldwide. They are positive-sense, single-stranded, non-enveloped RNA viruses with icosahedral geometry. Coxsackieviruses have two groups, A and B, each associated with different diseases. Coxsackievirus group A is known for causing hand-foot-and-mouth diseases while Group B, which contains six serotypes, can cause a varying range of symptoms like gastrointestinal distress myocarditis. Coxsackievirus B4 has a cell tropism for natural killer cells and pancreatic islet cells. Infection can lead to beta cell apoptosis which increases the risk of insulitis.

<span class="mw-page-title-main">Poliovirus</span> Enterovirus

A poliovirus, the causative agent of polio, is a serotype of the species Enterovirus C, in the family of Picornaviridae. There are three poliovirus serotypes: types 1, 2, and 3.

<span class="mw-page-title-main">Picornavirus</span> Family of viruses

Picornaviruses are a group of related nonenveloped RNA viruses which infect vertebrates including fish, mammals, and birds. They are viruses that represent a large family of small, positive-sense, single-stranded RNA viruses with a 30 nm icosahedral capsid. The viruses in this family can cause a range of diseases including the common cold, poliomyelitis, meningitis, hepatitis, and paralysis.

<i>Varroa destructor</i> Species of mite

Varroa destructor, the Varroa mite is an external parasitic mite that attacks and feeds on the honey bees Apis mellifera and Apis cerana. The disease caused by the mites is called varroosis.

<i>Dicistroviridae</i> Family of viruses

Dicistroviridae is a family of viruses in the order Picornavirales. Invertebrates, including aphids, leafhoppers, flies, bees, ants, and silkworms, serve as natural hosts. There are 15 species in this family, assigned to three genera. Diseases associated with this family include: DCV: increased reproductive potential. extremely pathogenic when injected with high associated mortality. CrPV: paralysis and death.

<i>Varroa</i> Genus of mites

Varroa is a genus of parasitic mesostigmatan mites associated with honey bees, placed in its own family, Varroidae. The genus was named for Marcus Terentius Varro, a Roman scholar and beekeeper. The condition of a honeybee colony being infested with Varroa mites is called varroosis.

<i>Aphthovirus</i> Genus of viruses

Aphthovirus is a viral genus of the family Picornaviridae. Aphthoviruses infect split-hooved animals, and include the causative agent of foot-and-mouth disease, Foot-and-mouth disease virus (FMDV). There are seven FMDV serotypes: A, O, C, SAT 1, SAT 2, SAT 3 and Asia 1, and four non-FMDV serotypes belonging to three additional species Bovine rhinitis A virus (BRAV), Bovine rhinitis B virus (BRBV) and Equine rhinitis A virus (ERAV).

<i>Deformed wing virus</i> Species of virus

Deformed wing virus (DWV) is an RNA virus, one of 22 known viruses affecting honey bees. While most commonly infecting the honey bee, Apis mellifera, it has also been documented in other bee species, like Bombus terrestris, thus, indicating it may have a wider host specificity than previously anticipated. The virus was first isolated from a sample of symptomatic honeybees from Japan in the early 1980s and is currently distributed worldwide. It is found also in pollen baskets and commercially reared bumblebees. Its main vector in A. mellifera is the Varroa mite. It is named after what is usually the most obvious deformity it induces in the development of a honeybee pupa, which is shrunken and deformed wings, but other developmental deformities are often present.

Animal viruses are viruses that infect animals. Viruses infect all cellular life and although viruses infect every animal, plant, fungus and protist species, each has its own specific range of viruses that often infect only that species.

<span class="mw-page-title-main">Iflaviridae</span> Family of viruses

Iflaviridae is a family of positive sense RNA viruses insect-infecting viruses. Some of the insects commonly infected by iflaviruses include aphids, leafhoppers, flies, bees, ants, silkworms and wasps. The name "Ifla" is derived from the name "Infectious flacherie virus", a member species. There is one genus (Iflavirus) and 16 species in this family.

Varroa sensitive hygiene (VSH) is a behavioral trait of honey bees (Apis mellifera) in which bees detect and remove bee pupae that are infested by the parasitic mite Varroa destructor. V. destructor is considered to be the most dangerous pest problem for honey bees worldwide. VSH activity results in significant resistance to the mites.

Cricket paralysis virus (CrPV) is a paralytic disease affecting crickets. It was initially discovered in Australian field crickets by Carl Reinganum and his colleagues at the Victorian Plant Research Institute. The disease spread rapidly through a breeding colony as well as through a laboratory population causing about 95% mortality. This was the first recorded isolate of the virus and is generally referred to as CrPVvic to distinguish it from subsequent isolates.

<span class="mw-page-title-main">Picornain 3C</span>

Picornain 3C is a protease found in picornaviruses, which cleaves peptide bonds of non-terminal sequences. Picornain 3C’s endopeptidase activity is primarily responsible for the catalytic process of selectively cleaving Gln-Gly bonds in the polyprotein of poliovirus and with substitution of Glu for Gln, and Ser or Thr for Gly in other picornaviruses. Picornain 3C are cysteine proteases related by amino acid sequence to trypsin-like serine proteases. Picornain 3C is encoded by enteroviruses, rhinoviruses, aphtoviruses and cardioviruses. These genera of picoviruses cause a wide range of infections in humans and mammals.

Dinocampus coccinellae paralysis virus (DcPV) is a single-stranded, positive-sense RNA virus of insects, in the picorna-like virus family Iflaviridae, which was first characterised in 2015. It asymptomatically infects the parasitic braconid wasp, Dinocampus coccinellae, and has been proposed to be associated with the paralytic effect the wasp has on its host, the spotted lady beetle, Coleomegilla maculata, which it turns into a so-called "zombie bodyguard" for its pupa.

Chronic bee paralysis virus (CBPV) commonly affects adult Apis mellifera honey bees and causes a chronic paralysis that can easily spread to other members of a colony. Bees infected with CBPV begin to show symptoms after 5 days and die a few days after. Chronic bee paralysis virus infection is a factor that can contribute to or cause the sudden collapse of honeybee colonies. Since honeybees serve a vital role in ecological resilience, it is important to understand factors and diseases that threaten them.

Aparavirus is a genus of viruses in the order Picornavirales, in the family Dicistroviridae. Invertebrates, honeybee, and bumblebees serve as natural hosts. There are six species in this genus. Diseases associated with this genus include: ABPV: paralysis. This virus plays a role in sudden collapse of honey bee colonies infested with the parasitic mite varroa destructor.

Triatoma virus (TrV) is a virus belonging to the insect virus family Dicistroviridae. Within this family, there are currently 3 genera and 15 species of virus. Triatoma virus belongs to the genus Cripavirus. It is non-enveloped and its genetic material is positive-sense, single-stranded RNA. The natural hosts of triatoma virus are invertebrates. TrV is a known pathogen to Triatoma infestans, the major vector of Chagas disease in Argentina which makes triatoma virus a major candidate for biological vector control as opposed to chemical insecticides. Triatoma virus was first discovered in 1984 when a survey of pathogens of triatomes was conducted in the hopes of finding potential biological control methods for T. infestans.

<i>Black queen cell virus</i> Species of virus

The black queen cell virus (BQCV) is a virus that infects honey bees, specifically Apis mellifera, Apis florea, and Apis dorsata. Infection of the latter two species is more recent and can be attributed to genetic similarity and geographical closeness. It is important to learn about this virus because it is one of the most common bee viruses and bees are the most important pollinators. The agricultural industry depends on the bee's pollination to increase its economic value.

The evolution of the Sacbrood virus (SBV) is characterized by the genomic changes that have occurred in SBV since its initial discovery in 1913, which have enabled the virus to continuously infect a wide array of honeybee colonies. SBV is single stranded RNA virus (genus: Iflavirus) that most commonly infects honeybee larvae, and is known to wipe out entire honeybee colonies quickly. Due to SBV, there has been sharp declines in honey bee populations in Europe, as well as a 30% decline each year in U.S. colonies. Studies on the evolution of SBV have arose in hopes to stop these colony devastations. SBV is one of the most widely studied honeybee viruses in terms of genomic analysis, leading to it having the highest number of complete genomes isolated compared to any other viruses known to honeybees. Through these genome studies, it has been found that there are two distinct lineages of SBV, each characterized by a high mutation rate, leading to multiple subtypes in both lineages. In studying how these lineages have evolved through time, new discoveries in their pathogenicity and different honeybee resistance mechanisms have been unveiled.

References

  1. http://www.techne.com/docs/sbpv.pdf [ bare URL PDF ]
  2. 1 2 Manley, Robyn (2017). "Condition-dependent virulence of slow bee paralysis virus in Bombus terrestris: are the impacts of honeybee viruses in wild pollinators underestimated?". Oecologia. 184 (2): 305–315. Bibcode:2017Oecol.184..305M. doi:10.1007/s00442-017-3851-2. PMC   5487845 . PMID   28361244.
  3. 1 2 3 Kalynych, Sergei (2016). "Virion structure of iflavirus slow bee paralysis virus at 2.6 Å resolution". Journal of Virology. 90 (16): 7444–7455. doi:10.1128/JVI.00680-16. PMC   4984619 . PMID   27279610.
  4. 1 2 Kalynych. "Slow Bee Paralysis Virus". Protein Data Bank in Europe.
  5. 1 2 3 4 5 6 Joachim, de Miranda (2010). "Genetic characterization of slow bee paralysis virus of the honeybee". Journal of General Virology. 91 (Pt 10): 2524–2530. doi: 10.1099/vir.0.022434-0 . PMID   20519455.
  6. Govan, V.A. (25 November 2000). "Analysis of the Complete Genome Sequence of Acute Bee Paralysis Virus Shows That It Belongs to the Novel Group of Insect-Infecting RNA Viruses". Virology. 277 (2): 457–463. doi: 10.1006/viro.2000.0616 . PMID   11080493.
  7. 1 2 3 Kalynych; et al. (2016). "Cryo-EM study of slow bee paralysis virus at low pH reveals iflavirus genome release mechanism". PNAS. 114 (3): 598–603. doi: 10.1073/pnas.1616562114 . PMC   5255585 . PMID   28053231.
  8. Denholm, C. H. (1999). Inducible honey bee viruses associated with varroa jacobsoni (PhD thesis). Keele, UK: University of Keele.
  9. Moore, P.; et al. (August 2014). "Honey Bee Viruses, the Deadly Varroa Mite Associates". Department of Entomology and Plant Pathology, the University of Tennessee, Knoxville TN.
  10. "Managing Varroa Mites in Honey Bee Colonies". NC State Extension. 23 Feb 2016.