Myxomatosis
Encyclopedia
Disease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...
that affects rabbits and is caused by the Myxoma virus
Myxoma virus
The Myxoma virus causes Myxomatosis in rabbits and was used as a pest control in Australia.- Structure :Virions are enveloped, have a surface membrane with lateral bodies. The envelope contains host-derived lipids and self-synthesized glycolipids. They are brick shaped and are about 250 nm in...
. It was first observed in Uruguay
Uruguay
Uruguay ,officially the Oriental Republic of Uruguay,sometimes the Eastern Republic of Uruguay; ) is a country in the southeastern part of South America. It is home to some 3.5 million people, of whom 1.8 million live in the capital Montevideo and its metropolitan area...
in laboratory rabbits in the late 19th century. It was introduced into Australia in 1950 in an attempt to control the rabbit population. (See Rabbits in Australia
Rabbits in Australia
In Australia, rabbits are a serious mammalian pest and are an invasive species. Annually, European rabbits cause millions of dollars of damage to crops.-Effects on Australia's ecology:...
.)
Effects of the disease
In rabbits of the genus Sylvilagus (cottontail rabbitCottontail rabbit
The cottontail rabbits are among the 16 lagomorph species in the genus Sylvilagus, found in the Americas.In appearance, most cottontail rabbits closely resemble the wild European Rabbit...
s), myxomatosis only causes localized skin tumors, but the European rabbit
European Rabbit
The European Rabbit or Common Rabbit is a species of rabbit native to south west Europe and north west Africa . It has been widely introduced elsewhere often with devastating effects on local biodiversity...
(Oryctolagus cuniculus) is more severely affected. At first, normally the disease is visible by lumps (myxomata) and puffiness around the head and genitals. It then may progress to acute conjunctivitis
Conjunctivitis
Conjunctivitis refers to inflammation of the conjunctiva...
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 may take place rapidly, often in as little as 48 hours. Death usually occurs within 14 days.
Treatment
Myxomatosis can be misdiagnosed as pasteurellosisPasteurellosis
Pasteurellosis is an infection with a species of the bacteria genus Pasteurella, which is found in humans and animals.Pasteurella multocida is carried in mouth and respiratory tract of several animals, notably cats. It is a small Gram negative bacillus with bipolar staining by Wayson stain...
, a bacterial infection which can be treated with antibiotics. Rabbits treated for pasteurellosis must often be treated with antibiotics for several weeks to several months. Some rabbits may require surgical intervention in order to remove purulent tissues and abscess. Once pasteurellosis has become well entrenched, however, there is no guarantee the animal will survive. By contrast, at this writing, there is no treatment for rabbits suffering myxomatosis, other than palliative care to ease the suffering of individual animals, and the treatment for secondary and opportunistic infections, in the hopes the treated animal will survive. Though the vectors of communication are similar, either contact with an infected animal, cage, feeding or water dishes, and insects, pasteurellosis can also be spread through breeding, specifically infecting the sexual organs of the animal. Likewise, it is advisable to arrive at the correct diagnosis for the benefit of both rabbit and owner.
In cases of myxomatosis and rabbit hemorrhagic disease (RHD), the owner is often urged to euthanize the animal to ease its suffering. Often the difference between diagnosing a fatal viral infection and a complex, but treatable, bacterial infection like pasteurellosis, will likely include medications, X-rays, surgery, convalescent, and follow-up care. While surgery and antibiotics may successfully treat pasteurellosis, they will not treat myxomatosis or RHD. Thus it is important to discern between untreatable diseases and treatable conditions. Myxomatosis and RHD are highly communicable, and untreatable at any stage, whereas rabbits suffering from diseases/conditions other than myxomatosis and RHD, such as poisoning, heat exhaustion, E. coli or Clostridium perfringens
Clostridium perfringens
Clostridium perfringens is a Gram-positive, rod-shaped, anaerobic, spore-forming bacterium of the genus Clostridium. C. perfringens is ever present in nature and can be found as a normal component of decaying vegetation, marine sediment, the intestinal tract of humans and other vertebrates,...
type E enterotoxemia
Enterotoxemia
Enterotoxemia is an infection by Clostridium perfringens which affects several types of domesticated animals, but is not known to affect humans. It is also known as overeating disease and can kill the animals within 2 hours.-External links:...
can benefit from timely veterinary intervention.
Spread of the disease
After its discovery in 1896 in imported rabbits in UruguayUruguay
Uruguay ,officially the Oriental Republic of Uruguay,sometimes the Eastern Republic of Uruguay; ) is a country in the southeastern part of South America. It is home to some 3.5 million people, of whom 1.8 million live in the capital Montevideo and its metropolitan area...
, 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.
Controversially, Myxomatosis was introduced to France by the bacteriologist Dr. Paul Armand Delille
Paul Armand Delille
Prof. Paul Felix Armand-Delille was a physician, bacteriologist, professor, and member of the French Academy of Medicine who unintentionally brought about the collapse of rabbit populations throughout much of Europe and beyond in the 1950s through the myxomatosis virus.Born in Fourchambault in...
, following his use of the virus to rid his private estate of rabbits in June 1952 (He inoculated two of the rabbits on his land).
International Herald Tribune, Wednesday, June 7, 2006, page 2. 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, being illegally imported onto an estate in West Sussex. 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. Unfortunately, the disease has wider consequences, apart from the death of rabbits: the Iberian Lynx
Iberian Lynx
The Iberian lynx, Lynx pardinus, is a critically endangered species native to the Iberian Peninsula in Southern Europe. It is one of the most endangered cat species in the world. According to the conservation group SOS Lynx, if this species died out, it would be one of the few feline extinctions...
, among others, is now almost extinct because the declining rabbit population which encompasses about 80% of its diet, has caused mass starvation. It is not uncommon for shooters to specifically target infected rabbits, viewing the act as being merciful. However, in 2005 the UK Land Registry conducted a survey of 16,000 hectares of its land and reported that the rabbit population had increased three-fold every two years – likely a product of increasing genetic resistance to the virus.
Myxomatosis is spread by direct contact with an affected animal or by being bitten by flea
Flea
Flea is the common name for insects of the order Siphonaptera which are wingless insects with mouthparts adapted for piercing skin and sucking blood...
s or mosquito
Mosquito
Mosquitoes are members of a family of nematocerid flies: the Culicidae . The word Mosquito is from the Spanish and Portuguese for little fly...
es that have fed on an infected rabbit. The myxomatosis virus does not replicate in these insect hosts, but can be physically carried by an insect's mouthparts, i.e. from an infected rabbit to another susceptible animal. Due to the potential of insect vector transmission, pet rabbits may be susceptible in enzootic areas and vaccination is highly recommended.
Use of vaccine
A vaccineVaccine
A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins...
is available for pet rabbits (ATCvet code: ), 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. However, there is no evidence that this could happen, and many pets in Australia continue to die from the introduced disease and the illegality of the vaccine.
There is at least one campaign to allow the vaccine for domestic pets.
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, many rabbits are genetically resistant to the original virus that was spread. The survival rate of diseased rabbits has now increased to 35% when in the 1950s it was near zero.Cultural reference
- The English poet Philip LarkinPhilip LarkinPhilip Arthur Larkin, CH, CBE, FRSL is widely regarded as one of the great English poets of the latter half of the twentieth century...
wrote a poem entitled "Myxomatosis", which was published in the 1955 volume The Less DeceivedThe Less DeceivedThe Less Deceived, first published in 1955, was Philip Larkin's first mature collection of poetry, having been preceded by the derivative North Ship from The Fortune Press and a privately printed collection...
. - The English punk band Flux Of Pink IndiansFlux Of Pink IndiansFlux of Pink Indians were an English anarcho-punk/post punk band, that originated from Bishop's Stortford, Hertfordshire, England.-Biography:...
recorded a song called "Myxomatosis" for their 1983 Album Strive to Survive Causing the Least Suffering PossibleStrive to Survive Causing the Least Suffering PossibleStrive To Survive Causing Least Suffering Possible is an album by the anarchist punk band Flux Of Pink Indians. The later CD reissue also includes the band's Neu Smell EP as five additional tracks, though in an incorrect track order and listing....
. - The Australian children's television show The FeralsThe FeralsThe Ferals is an Australian children's comedy television series created by Wendy Gray and Claire Henderson and produced by the ABC. It ran from 1994 to 1995, and it featured a mixture of people and animal puppets known as the "Ferals." It was lauded for its irreverent humour and distinctive...
featured a rabbit character whose name was Mixy. - In the novel The Year of the Angry RabbitThe Year of the Angry RabbitThe Year of the Angry Rabbit is a science fiction novel by Australian author Russell Braddon, in which giant mutant rabbits run amok in Australia while the Prime Minister uses a new super weapon to dominate the planet....
by Russell BraddonRussell BraddonRussell Reading Braddon was an Australian writer of novels, biographies and TV scripts. His chronicle of his four years as a prisoner of war, The Naked Island, sold more than a million copies....
, the Australian Prime Minister attempts to develop "supermyxomatosis" in order to kill off a second rabbit infestation. It ends up turning the rabbits into carnivorous plague carriers instead. The novel was adapted into the film Night of the LepusNight of the LepusNight of the Lepus, also known as Rabbits, is a 1972 American science fiction horror film based on the 1964 science fiction novel The Year of the Angry Rabbit. Released theatrically on October 4, 1972, it focuses on members of a small Arizona town who battle thousands of mutated, carnivorous killer...
. - In her memoir Bad BloodBad BloodBad Blood is an English phrase referring to enmity between two people or groups.The phrase may also refer to:-In film and television:* Bad Blood , starring Jack Thompson, about mass murderer Stanley Graham...
, the Welsh writer Lorna SageLorna SageLorna Sage was a Welsh-born academic, as well as an award-winning literary critic and author, known widely for her contribution to the consideration of women's writing.-Biography:...
gives a firsthand account of the 1953 spread of myxomatosis among rabbits in Hanmer, Wales. - The band RadioheadRadioheadRadiohead are an English rock band from Abingdon, Oxfordshire, formed in 1985. The band consists of Thom Yorke , Jonny Greenwood , Ed O'Brien , Colin Greenwood and Phil Selway .Radiohead released their debut single "Creep" in 1992...
recorded a song titled "Myxomatosis" appearing on their 2003 album Hail to the ThiefHail to the ThiefHail to the Thief is the sixth studio album by the English rock band Radiohead, released in June 2003 through Parlophone Records. After two Radiohead albums that featured heavily processed vocals, less guitar, and strong influence from experimental electronica and jazz, Hail to the Thief was seen...
, with lyrics including "I twitch and salivate like with myxomatosis". - In the book Watership DownWatership DownWatership Down is a classic heroic fantasy novel, written by English author Richard Adams, about a small group of rabbits. Although the animals in the story live in their natural environment, they are anthropomorphised, possessing their own culture, language , proverbs, poetry, and mythology...
, the characters refer to myxomatosis as "white blindness". - In his song "Donnie Darko", the comedian Tim MinchinTim MinchinTimothy David "Tim" Minchin is a British-Australian comedian, actor, and musician.Tim Minchin is best known for his musical comedy, which has featured in six CDs, three DVDs and a number of live comedy shows which he has performed internationally. He has also appeared on television in Australia,...
rhymes "Myxomatosis" with "Psychosis". - The Fast ShowThe Fast ShowThe Fast Show, known as Brilliant in the US, was a BBC comedy sketch show programme that ran for three series from 1994 to 1997 with a special Last Fast Show Ever in 2000. The show's central performers were Paul Whitehouse, Charlie Higson, Simon Day, Mark Williams, John Thomson, Arabella Weir and...
s Chanel 9 translates the number 12 as Myxomatosis- a compound of "Myxa", meaning two, and "matosis" aparrently meaning "teen"- in a sketch parodying lottery draw programmes. This, however, is contradicted by a sketch parodying televised awards ceremonies, which translates it as "Twelf".
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