Myxomatosis
The myxomatosis ( Kaninchenpest ) is a by the leporipox myxomatosis or myxomatosis virus, which the poxviruses heard induced viral disease , which is almost exclusively in domestic and wild rabbits occurs. Brown hares are largely insensitive to the disease.
Etiology and Distribution
Pathogen
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The causative agent of myxomatosis are viruses of the species Myxomatosevirus ( scientifically Myxoma virus , MYXV, outdated Leporipoxvirus myxomatosis ), which belong to the genus Leporipoxvirus in the subfamily Chordopoxvirinae of the smallpox viruses .
The virus particles ( virions ) of the myxomaviruses are enveloped and have a surface membrane with side bodies ( English lateral bodies ). The shell contains lipids derived from the host as well as virus-synthesized glycolipids . The virions are brick -shaped ( cuboid , English brick-shaped ) and have a diameter of 250 nm , a length of 300 nm and a height of 200 nm. The middle contains a biconcave core, as is characteristic of many smallpox viruses.
The genome is unsegmented (monopartite) and contains a single molecule of linear double-stranded DNA with a length of 160,000 nucleotides . The genome has a GC content of ~ 40% with terminal redundant sequences that are repeated at both ends.
The genome encodes 170 open reading frames ( english open reading frames , ORFs), twelve of which in the terminal inverted repeats duplicated are.
Transmission and dissemination
The virus is most often transmitted indirectly through stinging, blood-sucking insects such as mosquitoes and fleas. An effective mosquito repellent is therefore particularly important for larger populations. An increased insect population of the vectors in warm, humid summers and in autumn leads to an increased occurrence of the disease in these seasons. Furthermore, the virus can be transmitted with the algae and through direct contact from animal to animal through sniffing and contact with the mucous membrane.
In the course of an epidemic cycle, which usually begins with a highly virulent virus strain and results in a mortality rate of up to 100%, progressively milder or atypical courses occur through weakening and adaptation of the virus to the hosts. The myxomatosis virus, which originally came from South America , is spread throughout Central Europe. The North and South American rabbit species ( cottontail rabbits ) show little or no symptoms and represent a natural reservoir of pathogens . Brown hares are only slightly sensitive to the myxomatosis virus. Even if the infection pressure is high, a maximum of 1% of brown hares fall ill.
After Australia it was deliberately to control the local rabbit population introduced. In Europe, the virus was introduced in 1952 by Paul-Félix Armand-Delille . In order to decimate the rabbit population on his fenced country estate Maillebois , he had the Brazilian myxomatosis virus strain sent from Switzerland in 1952 and infected two wild rabbits on June 14, 1952.
Clinic / symptoms
Acute course
The first symptoms appear after an incubation period of three to nine days. The rabbit appears apathetic , shows reluctance to eat and drinks little. In the acute course of the disease, swelling and inflammation occur in the area of the eyelids, the mouth, the ears, the lips and the genital area. After about 10 to 14 days, the disease usually ends with death.
Chronic course
With a chronic course of the disease, more pustules appear. A cure is possible in individual cases. In some cases the rabbit recovers ( spontaneously heals ), but still carries the disease.
Treatment and healing prospects
There is no specific treatment for myxomatosis. Usually the animal is treated with antibiotics to reduce secondary inflammation caused by bacteria. In addition, active substances can be administered that cause short-term immunity in rabbits (paramunity inducers). Depending on the virulence , the lethality is 20 to 100%. As a preventive measure, however, vaccination with an attenuated live vaccine every six months can protect against infection . Unvaccinated, diseased animals can be relieved of pain by giving them eye drops and letting them inhale saline solution . Some animals survive without vaccination. Rabbits to be newly introduced into a susceptible herd should be quarantined for 14 days and vaccinated.
See also
swell
- Oskar-Rüger Kaaden: Myxomatosis. In: Bernd Liess, Oskar-Rüger Kaaden (Ed.): Virus infections in domestic and farm animals. Domestic mammals, fish. 2nd, updated and exp. Edition. Schlütersche, Hannover 2003, ISBN 3-87706-745-X .
- Anja Ewringmann: Key symptoms in rabbits. Diagnostic guide and therapy. 2., revised. Edition. Thieme, Stuttgart 2010, ISBN 978-3-8304-1090-4 .
Web links
- Astrid Heintze-Furch: Myxomatosis. In: kaninchenchannel.net June 2001, updated in April 2003 (detailed description)
Individual evidence
- ↑ a b c d e ICTV: ICTV Taxonomy history: Variola virus , EC 51, Berlin, Germany, July 2019; Email ratification March 2020 (MSL # 35)
- ↑ Cheryl Cameron et al: The Complete DNA Sequence of Myxoma Virus . In: Virology . tape 264 , no. 2 , November 25, 1999, p. 298-318 , doi : 10.1006 / viro.1999.0001 , PMID 10562494 .
- ↑ Peter Kerr et al: Evolutionary History and Attenuation of Myxoma Virus on Two Continents . In: PLoS Pathogens . tape 8 , no. 10 , October 4, 2012, p. e1002950 , doi : 10.1371 / journal.ppat.1002950 , PMID 23055928 , PMC 3464225 (free full text).
- ↑ Rainer Holubek: A closed vaccination cover protects against myxomatosis and RHD. In: The small animal breeder. Rabbit newspaper. 5/2008, ISSN 1613-6357 .
- ↑ Viruses came in the mail . In: Der Spiegel . No. 29 , 1954 ( online - 14 July 1954 ).
