Myxomatosis

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Myxomatosis (commonly called 'myxi') is a disease which affects rabbits. It is caused by the Myxoma virus. First observed in Uruguay in the late 1800s, it was deliberately introduced into Australia in 1950 in an attempt to control rabbit infestation and population there; see rabbits in Australia. It was introduced illegally to France in 1952 and as a result spread to the rest of Europe.

Contents 1 Effects of the disease 2 Spread of the disease 3 Use of vaccine 4 Natural resistance 5 Cultural references 6 References 7 External links

[edit] Effects of the disease

In rabbits of the genus Sylvilagus (cottontail rabbits), myxomatosis only causes localized skin tumors, but the European rabbit (Oryctolagus cuniculus) is more severely affected.^[1] It is crucial^[why?] to prevent the misdiagnosis of myxomatosis with conditions such as pasteurellosis, rabbit haemorrhagic disease, poisoning, heat exhaustion, E. coli or Clostridium perfringens type E enterotoxemia. At first, normally the disease is visible by lumps (myxomata) and puffiness around the head and genitals. It then may progress to acute conjunctivitis and possibly blindness; however, this also may be the first indication of the disease. The rabbits become listless, lose appetite, and develop a fever. Secondary bacterial infections occur in most cases which cause pneumonia and purulent inflammation of the lungs. In typical cases where the rabbit has no resistance, death takes an average of 14 days.^{[citation needed]}.

[edit] Spread of the disease

After its discovery in 1896 in imported rabbits in Uruguay, a relatively harmless strain spread quickly throughout the wild populations in South America.

In Australia, the virus was first field-tested for population control in 1938. A full-scale release was performed in 1950. It was devastatingly effective, reducing the estimated rabbit population from 600 million to 100 million in two years. However, the rabbits remaining alive were those least affected by the disease. Genetic resistance to myxomatosis was observed soon after the first release and most rabbits acquired partial immunity in the first two decades. Resistance has been increasing slowly since the 1970s, and the disease now only kills about 50% of infected rabbits. In an attempt to increase that number, a second virus (rabbit calicivirus) was introduced into the rabbit population in 1996.

Myxomatosis was unintentionally introduced to France by the bacteriologist Dr. Paul Armand Delille, following his use of the virus to rid his private estate of rabbits in June 1952 (controversially, he inoculated two of the rabbits on his land). Within four months the virus had spread 50 km; Armand suspected this was due to poachers taking infected rabbits from his estate. By 1954, 90% of the wild rabbits in France were dead. The disease spread throughout Europe. It reached the UK in 1953, apparently without human action. Some in the UK deliberately spread the disease, placing sick rabbits in burrows, while many others deplored the cruelty and suffering. The government refused to legislate to make deliberate spread of the disease illegal. By 1955, about 95% of rabbits in the UK were dead. Rabbits suffering in the last stages of the disease, commonly called "mixy" or "myxie" rabbits, are still a common sight in the UK^{[citation needed]}. Unfortunately, the disease has wider consequences, apart from the death of rabbits: the Spanish Lynx among others is now almost extinct because the declining rabbit population, encompassing 90% of its diet, has caused mass starvation. It is not uncommon for shooters to specifically target infected rabbits, viewing the act as being merciful. In 2005 the UK Land Registry conducted a survey of 16,000 hectares of its land and reported that the rabbit population had increased 3 fold every two years.

Myxomatosis is spread by fleas and mosquitoes. Therefore, pet rabbits are susceptible and vaccination is highly recommended^[2].

[edit] Use of vaccine

A vaccine is available for pet rabbits (ATCvet code: QI08AD02)^[2], but is illegal in Australia due to fears that the immunity conferred by the vaccine could be transmitted through the wild rabbit population, since the vaccine uses a live virus, the Shope fibroma virus.

[edit] Natural resistance

The development of resistance to the disease seems to have taken different courses. In Australia, the virus initially killed rabbits very quickly, about 4 days after infection. This gave little time for the infection to spread. However, a less virulent form of the virus has become prevalent there, spreading more effectively by being less lethal. In Europe, rabbits that are genetically resistant to the original virus have spread. The survival rate of diseased rabbits has now increased to 35% when in the 1950s it was zero. It is conjectured that this is because the main transmission vector in Australia is the mosquito, while in Europe it is the rabbit flea.

[edit] Cultural references

• Myxomatosis. (Judge, Jury & Executioner.) is the name of a song on the 2003 album Hail to the Thief, by Radiohead.
• Myxomatosis is the name of a poem by Philip Larkin from his 1955 anthology The Less Deceived.
• Myxomatosis Failed is the title of folk/rock quartet ilyAIMY 2003 album. It was followed up in 2005 with Myxomatosis Took Its Toll. [1]
• Myxomatosis is the name of a song on the 1983 album Strive to Survive Causing the Least Suffering Possible by the English anarcho-punk band Flux of Pink Indians.
• Myxomatosis appears in the T.Rex lyrics for the song "Left Hand Luke": "Myxomatosis is an animal's disease, but I got so shook up mama that it ate away my knees, and I'm Left Hand Luke and the beggar boys, O yes we are."
• Ben Elton said of the novelty pop act Jive Bunny in The Man From Auntie "I have never seen a more coherent argument for myxomatosis."
• The Hitchhiker's Guide to the Galaxy mentions myxomatosis in Chapter 24. It jokingly applies the disease to mice.
• Originating on the Australian children's TV show The Ferals in 1994, there is a pink rabbit character named "Mixy". She also was in the spinoff, Feral TV. Due to the popularity of the character, she was later given her own show, presenting children's shows on the Australian Broadcasting Corporation.
• In the classic Richard Adams book Watership Down (featuring rabbit characters), myxomatosis is the disease the rabbits refer to as the "white blindness."
• Myxomatosis is the name of a short poem by Spike Milligan
• In the film, Meet The Feebles, it is implied that the rabbit in the film has contracted AIDS (due to his extreme promiscuity). In fact, the disease he is suspected to have is myxomatosis, although it is later revealed to be just "bunny pox".
• Singer, actor and comedian Tim Minchin cited Donnie Darko as "an excellent example of why they developed myxomatosis" in a song for ABC's series counting down Australia's favourite films.
• Myxomatose is a stabile (standing mobile) sculpture by Alexander Calder, created in 1953, it is unknown why he named his sculpture after Myxomatosis.
• In Russell Braddon's 1965 novel The Year of the Angry Rabbit, Australians develop "super-myxomatosis" in an attempt to overcome rabbits' immunity to myxomatosis. Finding it to be the perfect biological weapon, Australia uses it to take over the world - until it is overrun by super-myxomatosis-immune rabbits.
• In The Alfred Hitchcock Hour, episode entitled Consider Her Ways (Season 3, Episode 11: Original Air Date 28 Dec 1964) Myxomatosis is the virus that is being developed for biological control of rats. The virus mutates and kills all male humans. This spares only women, who have patterned their society after that of ants. This is seen in a hallucination/vision by the character played by Barbara Barrie.
• In an episode of Are You Being Served?, Miss Brahms believes that Mrs Slocombe's fiancé (Mr Mataxis) is called Myxomatosis.
• In the popular flash game, titled "Bunny Invasion", Myxomatosis is able to be purchased as a weapon against the enemy for obvious reasons.

[edit] References

[edit] External links

• An interview with Frank Fenner
• Coalition against Myxomatosis - an organisation campaigning for legalization of vaccine in Australia.
• Society & Animals Journal of Human-Animal Studies, Volume 9, Number 2, 2001