Turkeypox virus

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Turkeypox virus
Virus classification OOjs UI icon edit-ltr.svg
(unranked): Virus
Realm: Varidnaviria
Kingdom: Bamfordvirae
Phylum: Nucleocytoviricota
Class: Pokkesviricetes
Order: Chitovirales
Family: Poxviridae
Genus: Avipoxvirus
Species:
Turkeypox virus

Turkeypox virus is a virus of the family Poxviridae and the genus Avipoxvirus that causes turkeypox. [1] It is one of the most common diseases in the wild turkey (Meleagris gallopavo) population. [2] Turkeypox, like all avipoxviruses, is transmitted either through skin contact or by arthropods (typically mosquitos) acting as mechanical vectors. [3]

Contents

Turkeypox virus was first reported in a turkey flock in New York by E.L. Burnett, [4] and may be identified by nodular proliferative skin lesions on the non-feathered parts of the body and in the fibrino-necrotic and proliferative lesions in the mucous membrane of the upper respiratory tract. [5]

Viral classification

Turkeypox virus is a member of the family Poxviridae and is in the genus Avipoxvirus. There are currently nine other species within this genus, all of which are viruses: Fowlpox, Juncopox, Mynahpox, Psittacinepox, Sparrowpox, Starlingpox, Pigeonpox, Canarypox, and Quailpox. [6]

Avipoxvirus infections have been reported in over 232 bird species in 23 orders of birds, but most of our knowledge comes from the study of fowlpox virus and canarypox virus as they are the only species with full genome sequences available. [6]

Structure and genome

Turkeypox virus, like other Avipoxviruses, is an enveloped, double-stranded DNA virus with a large, linear genome of approximately 300 kilobytes in size. [6] The central region of the genome contains at least 90–100 homologous genes that are involved in viral replication, and these genes are generally relatively conserved among Poxviruses. [6] This is in contrast to the more variable, terminally located genes that have been shown to encode a diverse array of proteins involved in host range restriction. [6]

Replication

Avipoxviruses follow the same replication cycle that all poxviruses use. Poxvirus is unique from other DNA viruses in respect to its locale of replication in the cell. Poxvirus replicates in the cytoplasm instead of the nucleus. This phenomenon is made possible by the fact that poxvirus encodes its own transcriptional machinery, so poxvirus uses only the host translational machinery to produce its mature virions. [7] [8]

Entry and initial uncoating

Poxvirus starts its replication cycle by attaching to host cell receptors. These receptors are thought to be glycosaminoglycan. Once attached the virus uncoats by first losing its outer membrane and then fusing with the cellular membrane so that its core particle containing the genome can be released into the cytoplasm. [7] [8]

Early transcription

Once in the cytoplasm poxvirus then starts to express early genes. These early genes are expressions are mediated by virally encoded transcriptional machinery that includes: a heterodimeric transcription factor (vETF), a seven-subunit RNA polymerase, the heterodimeric capping enzyme/ termination protein, and the heterodimeric poly(A) polymerase. Also important for transcription is a capsidated RNA helicase, and two NTPases. These early transcripts are released from the core and translated by host ribosomes. [7] [8]

Translocation

The viral core is now translocated to the outside of the cell nucleus. [7]

Second uncoating

After these early genes are transcribed and translated there is a second uncoating step in which the rest of the genome is released and exposed to the previously produced replications proteins. The viral genome is now replicated as concatamers and transcription and translation of intermediate genes (mainly coding for transcription factors) occurs. [7] [8]

Late transcription

Late viral genes are now being transcribed (most encode for structural proteins, enzymes and transcriptions factors) and are then translated. [7]

Assembly and release

The concatameric intermediates produced earlier are now resolved into double strand DNA and packaged in the late viral proteins to produce and immature virions (IV). The immature virions mature through an unknown mechanism that may involve processing by the Golgi apparatus in the cell. They are now mature virions that are release from the cell by either lysing the cell or budding out from the membrane. It is through budding that they acquire their envelope. [7]

Tropism

Avipoxviruses, like all viruses, is an obligate intracellular parasite. It uses host translational machinery to replicate its genome. Avipoxviruses only infect birds, particularly wild fowl, and in this case, wild turkey (Meleagris gallopavo). Avipoxviruses are not able to complete their replication in non-avian species. Transmission of avipoxvirus occurs through a mosquito vector. [9]

Related Research Articles

<i>Poxviridae</i> Family of viruses

Poxviridae is a family of double-stranded DNA viruses. Vertebrates and arthropods serve as natural hosts. There are currently 83 species in this family, divided among 22 genera, which are divided into two subfamilies. Diseases associated with this family include smallpox.

<i>Parapoxvirus</i> Genus of viruses

Parapoxvirus is a genus of viruses, in the family Poxviridae, in the subfamily Chordopoxvirinae. Like all members of the family Poxviridae, they are oval, relatively large, double-stranded DNA viruses. Parapoxviruses have a unique spiral coat that distinguishes them from other poxviruses. Parapoxviruses infect vertebrates, including a wide selection of mammals, and humans.

<span class="mw-page-title-main">Viral replication</span> Formation of biological viruses during the infection process

Viral replication is the formation of biological viruses during the infection process in the target host cells. Viruses must first get into the cell before viral replication can occur. Through the generation of abundant copies of its genome and packaging these copies, the virus continues infecting new hosts. Replication between viruses is greatly varied and depends on the type of genes involved in them. Most DNA viruses assemble in the nucleus while most RNA viruses develop solely in cytoplasm.

<i>Molluscum contagiosum virus</i> Species of virus

Molluscum contagiosum virus (MCV) is a species of DNA poxvirus that causes the human skin infection molluscum contagiosum. Molluscum contagiosum affects about 200,000 people a year, about 1% of all diagnosed skin diseases. Diagnosis is based on the size and shape of the skin lesions and can be confirmed with a biopsy, as the virus cannot be routinely cultured. Molluscum contagiosum virus is the only species in the genus Molluscipoxvirus. MCV is a member of the subfamily Chordopoxvirinae of family Poxviridae. Other commonly known viruses that reside in the subfamily Chordopoxvirinae are variola virus and monkeypox virus.

<span class="mw-page-title-main">Fowlpox</span> Viral disease of poultry

Fowlpox is the worldwide disease of poultry caused by viruses of the family Poxviridae and the genus Avipoxvirus. The viruses causing fowlpox are distinct from one another but antigenically similar, possible hosts including chickens, turkeys, quail, canaries, pigeons, and many other species of birds. There are two forms of the disease. The first is spread by biting insects and wound contamination, and causes lesions on the comb, wattles, and beak. Birds affected by this form usually recover within a few weeks. The second is contracted by inhalation or ingestion of the virus via dust or aerosols, leading to the 'diphtheritic form' of the disease, in which diphtheritic membranes form in the mouth, pharynx, larynx, and sometimes the trachea. The prognosis for this form is poor.

<span class="mw-page-title-main">Canarypox</span> Viral disease of birds

Canarypox virus (CNPV) is an Avipoxvirus and etiologic agent of canarypox, a disease of wild and captive birds that can cause significant losses. Canarypox can enter human cells, but it cannot survive and multiply in human cells. There is a live viral vaccine available which may have beneficial properties against human cancer when used as a mammalian expression vector.. Furthermore, the POXIMUNE® C vaccine does offer direct protection against CNPV in susceptible birds.

Avipoxvirus is a genus of viruses within the family Poxviridae. Poxviridae is the family of viruses which cause the afflicted organism to have poxes as a symptom. Poxviruses have generally large genomes, and other such examples include smallpox and monkeypox. Members of the genus Avipoxvirus infect specifically birds. Avipoxviruses are unable to complete their replication cycle in non-avian species. Although it is comparably slow-spreading, Avipoxvirus is known to cause symptoms like pustules full of pus lining the skin and diphtheria-like symptoms. These diphtheria-like symptoms might include diphtheric necrotic membranes lining the mouth and the upper respiratory tract. Like other avian viruses, it can be transmitted through vectors mechanically such as through mosquitoes. There is no evidence that this virus can infect humans.

Chordopoxvirinae is a subfamily of viruses in the family Poxviridae. Vertebrates and arthropods serve as natural hosts. Currently, 52 species are placed in this subfamily, divided among 18 genera. Diseases associated with this subfamily include smallpox.

Entomopoxvirinae is a subfamily of viruses, in the family Poxviridae. Insects, human, vertebrates, and arthropods serve as natural hosts. There are currently 31 species in this subfamily, divided among 4 genera with one species unassigned to a genus. Diseases associated with this subfamily include: impairment of motility and development.

Capripoxvirus is a genus of viruses in the subfamily Chordopoxvirinae and the family Poxviridae. Capripoxviruses are among the most serious of all animal poxviruses. All CaPV are notifiable diseases to the OIE. Sheep, goat, and cattle serve as natural hosts. These viruses cause negative economic consequences by damaging hides and wool and forcing the establishment of trade restrictions in response to an outbreak. The genus consists of three species: sheeppox virus (SPPV), goatpox virus (GTPV), and lumpy skin disease virus (LSDV). They share no serological relationship with camel pox, horse pox, or avian poxes. Capripoxviruses for sheeppox and goatpox infect only sheep and goat respectively. However, it is probable that North American relatives, the mountain goat and mountain sheep, may be susceptible to the strains but has not been experimentally proven. Lumpy skin disease virus affects primarily cattle, but studies have been shown that giraffes and impala are also susceptible to LSDV. Humans cannot be infected by Capripoxviruses.

Alphaentomopoxvirus is a genus of viruses, in the family Poxviridae, in the subfamily Entomopoxvirinae. Coleoptera insects serve as natural hosts. There are seven species in this genus.

Betaentomopoxvirus is a genus of viruses, in the family Poxviridae, in the subfamily Entomopoxvirinae. Lepidoptera and orthoptera insects serve as natural hosts. There are 16 species in this genus.

Cervidpoxvirus is a genus of viruses in the family Poxviridae in the subfamily Chordopoxvirinae. Deer serve as natural hosts. Only one species is in this genus: Mule deerpox virus.

Gammaentomopoxvirus is a genus of viruses, in the family Poxviridae, in the subfamily Entomopoxvirinae. Lepidoptera and orthoptera insects serve as natural hosts. There are six species in this genus.

Leporipoxvirus is a genus of viruses, in the family Poxviridae, in the subfamily Chordopoxvirinae. Lagomorphs and squirrels serve as natural hosts. There are four species in this genus. Diseases associated with this genus include: myxomatosis.

Crocodylidpoxvirus is a genus of viruses, in the family Poxviridae, in the subfamily Chordopoxvirinae. Crocodiles serve as natural hosts. There is only one species in this genus: Nile crocodilepox virus. Diseases associated with this genus include: nodular skin lesions in young animals. Symptoms vary from a nonfatal dermatitis to more severe disease characterized by ophthalmia, rhinitis resulting in asphyxia, and debilitating illness with stunting and high mortality.

Raccoonpox virus (RCN) is a double-stranded DNA virus and a member of the orthopoxviruses in the family Poxviridae and subfamily Chordopoxvirinae which consists of eight genera: Avipoxvirus, Capripoxvirus, Leporipoxvirus, Molluscipoxvirus, Orthopoxvirus, Parapoxvirus, Suipoxvirus and Yatapoxvirus Vertebrates are the natural host of Chordopoxvirinae subfamily viruses. More specifically, raccoons are the natural hosts of RCN. RCN was isolated in 1961 from the upper respiratory tissues of 2 raccoons in a group of 92 observably healthy raccoons trapped close to Aberdeen, Maryland.

A kinetic class, also known as a temporal class, is a grouping of genes in a viral genome that are expressed at the same time during the viral replication cycle. Five of the human DNA viral families have multiple kinetic classes: Poxviridae, Herpesviridae, Adenoviridae, Papillomaviridae, and Polyomaviridae. All of the genes in a particular kinetic class are activated by the same mechanism: either by the process of the virus entering the cell and uncoating, or by the products of an earlier kinetic class in what is known as a transcriptional cascade. Generally speaking, earlier kinetic classes code for enzymes that direct the viral replication process, and later kinetic classes code for structural proteins to be packaged into virions

<i>Red deerpox virus</i> Species of virus

Red deerpox virus (RDPV) is a species of virus in the genus Parapoxvirus. It has been reported in deer in New Zealand, and in wild ruminants in Italy.

<i>Avian metaavulavirus 2</i> Species of virus

Avian metaavulavirus 2, formerly Avian paramyxovirus 2, is a species of virus belonging to the family Paramyxoviridae and genus Metaavulavirus. The virus is a negative strand RNA virus containing a monopartite genome. Avian metaavulavirus 2 is one of nine species belonging to the genus Metaavulavirus. The most common serotype of Avulavirinae is serotype 1, the cause of Newcastle disease (ND). Avian metaavulavirus 2 has been known to cause disease, specifically mild respiratory infections in domestic poultry, including turkeys and chickens, and has many economic effects on egg production and poultry industries. The virus was first isolated from a strain in Yucaipa, California in 1956. Since then, other isolates of the virus have been isolated worldwide.

References

  1. ↑ Timoney, John Francis (1988), Hagan and Bruner's Microbiology and Infectious Diseases of Domestic Animals, Cornell University Press, p. 433, ISBN   978-0-8014-1896-9
  2. ↑ Wright, Elizabeth J.; Nayar, Jai K.; Forrester, Donald J. (January 2005). "Interactive effects of turkeypox virus and Plasmodium hermani on Turkey poults". Journal of Wildlife Diseases. 41 (1): 141–148. doi: 10.7589/0090-3558-41.1.141 . PMID   15827220. S2CID   1071992.
  3. ↑ Wobeser, Gary A. (1997), Diseases of Wild Waterfowl, Springer, p. 50, ISBN   978-0-306-45590-2
  4. ↑ Singh, Alka; Dash, B.B.; Kataria, J. M.; Dandapat, S.; Dhama, K. (2003). "Characterisation of an indian isolate of turkey pox virus". Indian Journal of Comparative Microbiology, Immunology and Infectious Diseases. 24 (2): 149–152.
  5. ↑ Prukner-Radovčić, E.; Lüschow, D.; Grozdanić, I. Ciglar; Tišljar, M.; Mazija, H.; Vranešić, Đ.; Hafez, H. M. (2006). "Isolation and Molecular Biological Investigations of Avian Poxviruses from Chickens, a Turkey, and a Pigeon in Croatia". Avian Diseases. 50 (3): 440–444. doi:10.1637/7506-012006R.1. JSTOR   4099085. PMID   17039847. S2CID   28158634.
  6. 1 2 3 4 5 Weli, Simon C; Tryland, Morten (December 2011). "Avipoxviruses: infection biology and their use as vaccine vectors". Virology Journal. 8 (1): 49. doi: 10.1186/1743-422X-8-49 . PMC   3042955 . PMID   21291547.
  7. 1 2 3 4 5 6 7 Keckler, M. Shannon (19 August 2010). "Poxvirus Replication Cycle". Microbe Library. American Society for Microbiology. Archived from the original on 22 December 2015.
  8. 1 2 3 4 Moss, B. (1 September 2013). "Poxvirus DNA Replication". Cold Spring Harbor Perspectives in Biology. 5 (9): a010199. doi:10.1101/cshperspect.a010199. PMC   3753712 . PMID   23838441.
  9. ↑ McFadden, Grant (March 2005). "Poxvirus tropism". Nature Reviews Microbiology. 3 (3): 201–213. doi:10.1038/nrmicro1099. PMC   4382915 . PMID   15738948.
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