Canarypox

Source: Wikipedia, the free encyclopedia.
Canarypox virus
Virus classification Edit this classification
(unranked): Virus
Realm: Varidnaviria
Kingdom: Bamfordvirae
Phylum: Nucleocytoviricota
Class: Pokkesviricetes
Order: Chitovirales
Family: Poxviridae
Genus: Avipoxvirus
Species:
Canarypox virus
Canary bird
(Serinus canaria) with its typical yellow colouration.

Canarypox virus (CNPV) is an

QI01KD01 (WHO)). Furthermore, the Poximune C vaccine does offer direct protection against CNPV in susceptible birds.[3]

Generally CNPV is considered a disease of

nightingales, and is associated with higher mortality rates when compared to other avian pox viruses.[4] In some instances, mortality approaches 100%.[4] Avian pox viruses also cause significant economic losses in domestic poultry and remain a problem in the conservation of endemic bird species inhabiting islands.[5]

The general symptoms of CNPV are similar to those of other species of avian pox viruses and are characterised by pustules and diphtheria or pneumonia-like symptoms.[1]

Classification

Canarypox virus (CNPV) is a member of the Poxviridae family. Canarypox viruses, as with other bird pox viruses, are in the genera of Avipoxvirus. Nine other species are also in the genus

Turkeypox virus and Quailpox virus.[6]

It has thus far been reported that around 232 bird species (from 23 disparate orders) are affected by avian pox virus.[7]

Structure and replication

CNPV is an

poxviruses are characterised by having exceptionally large physical dimensions, approximately 330 nm×280 nm×200 nm.[6]

The

genes have been found.[8] The shape of all poxviruses resembles something of a 'rounded brick' and remains determined by the specific envelope around the virus.[9]

The process which further characterises the poxvirus family is that replication occurs in the cytoplasm and utilises a specific virus-made structure for replication, the 'virosome'.[10]

Furthermore,

vaccinia virus is commonly used as a prototype and can be consulted for further information.[citation needed
]

Transmission

The most common form of spread of CNPV is by

farms, where the contact rate of birds is high.[13]

When the virus is transmitted directly, this would usually occur through aerosols, consumption of infected bird tissue or by general contact with the diseased bird. Healthy birds are at increased risk of acquiring the disease through existing wounds or scabs when in close contact with diseased birds.[1]

The typical incubation period for the virus is between 5–10 days.[14]

Symptoms

CNPV

cutaneous) and/or wet (diphtheritic) symptoms (both forms can occur at the same time).[12]

The dry form is the most frequently observed. At the beginning of the disease, small white/yellow blisters form on the uncovered parts of the skin. As the disease progresses blisters get progressively larger and form nodules where the virus can multiply. When the nodules coalesce and burst, scabs are formed leaving rough, dry and pigmented areas on the skin where the nodules were.[12]

Electron micrograph
of an epidermal cell showing Poxvirus infection

This form of the disease is usually mild and does not cause death. The chances of mortality increase when the dry form occurs together with the wet (diphtheritic) form. The wet form symptoms include an enlarged

spleens.[15]

Observations under the

epidermis, feather follicles, sinuses and oral mucosa lining.[16]

Apart from the symptoms mentioned above, more general signs of infection include weight loss, loss of feathers and scaly skin on the head, neck and back.[1] Secondary bacterial infections are common with both forms of the disease, having the potential to cause pneumonia or other bacterial infections at the sites of blistering.[1]

Treatment

Currently there is no treatment available.[14]

Diseased birds should however be admitted to a

necrotic tissues is common.[12]

By keeping diseased birds in warmer temperatures and ensuring daily eye rinsing with 1-2%

lesions.[1]

Medical

Avian prevention

A live attenuated CNPV

canary birds and other passerine birds.[3] The brand name 'Poximune® C' by Ceva is a freeze-dried vaccine, administered by the 'wing web' method to healthy, susceptible passerine birds who have reached at least four weeks of age.[3] Booster vaccination is recommended every 6–12 months if the risk of disease remains high.[3] Pox lesion formation around the vaccination area is indicative that the vaccine has been effective. The vaccine should not be administered during egg production or in the 4 weeks prior to this.[3]

In a Hawaiian study Poximune® provided treatment in some birds, with their symptoms lasting only a few weeks, others developed necrosis and some died or had symptoms for two months, and some birds needed another vaccine as the first vaccine did not work. Therefore, a range of symptoms can be observed in a clinical setting, while giving unambiguous results. [17]

Mammalian medicine

CNPV has been used recently as a mammalian

antigens to the hosts immune system.[8]

Although veterinary CNPV recombinant vaccines exist, recent attention has focussed on its use in human medicine with several human vaccines using this expression system undergoing

cancers; such as melanoma and colorectal cancers.[8]

A strain of

interleukin-2 called vCP1338 is used to treat cats with fibrosarcoma.[20]

More information can be found in an review by Weli et al, 2011.[21]

Threats

Canarypox virus remains a constant threat to wild birds.

Galapagos. Here they have experienced dramatic losses in bird numbers.[22] Many more have become classified as endangered species due to CNPV. The disease is mainly spread by mosquitoes and mites in these regions, which were introduced during European colonisation.[22] Canarypox, together with avian malaria, are the most devastating diseases for birds on the island of Hawaii and surrounding regions.[22]

References

  1. ^ a b c d e f "Canary Pox Virus". BeautyOfBirds, formerly AvianWeb. Retrieved 22 March 2012.
  2. PMID 17947686
    .
  3. ^ a b c d e f "Poximune C". Drugs.com. Retrieved 22 March 2012.
  4. ^ a b "VaxQuery Database". Canarypox virus. VaxQuery. Archived from the original on 14 January 2020. Retrieved 22 March 2012.
  5. S2CID 8194562
    .
  6. ^ a b King, Andrew (2012). Virus Taxonomy: Ninth Report of The International Committee on the Taxonomy of Viruses the International Committee on Taxonomy of. International Union of Microbiological Societies. p. 298.
  7. PMID 16422070
    .
  8. ^
    PMID 14671117
    .
  9. PMID 21931553
    .
  10. S2CID 3094141
    .
  11. ^
    PMID 21183678
    .
  12. ^ a b c d e "Department of Natural Resources". Michigan Government. Retrieved 22 March 2012.
  13. ^ "The Different Pox Diseases in Birds". PetCareTips. Retrieved 22 March 2012.
  14. ^ a b "Canary Pox". Pet Health & Care. Retrieved 8 July 2020.
  15. ISBN 978-0123751584
    .
  16. ^
    PMID 19937516
    .
  17. ^ hawaii.edu https://hilo.hawaii.edu › hcsuPDF Efficacy of commercial canarypox vaccine for protecting Hawai'i ...
  18. ^ Skinner, Mike. "Vaccine Vectors". Imperial College London. Archived from the original on 12 July 2012. Retrieved 22 March 2012.
  19. PMID 8735555
    .
  20. ^ "EPAR summary for the public: Oncept IL-2 (Feline interleukin-2 recombinant canary pox virus) [EMA/151380/2013 EMEA/V/C/002562]" (PDF). European Medical Agency. 2013.
  21. PMID 21291547
    .
  22. ^
    PMID 21249151
    .
Retrieved from "https://en.wikipedia.org/w/index.php?title=Canarypox&oldid=1204649899"