Myxomatosis

October 31, 2016

What is Myxomatosis?

Myxomatosis is caused by the myxoma virus, a poxvirus spread between rabbits by close contact and biting insects such as fleas and mosquitoes. The virus causes swelling and discharge from the eyes, nose and anogenital region of infected rabbits. Most rabbits die within 10-14 days of infection however highly virulent strains of the myxoma virus may cause death before the usual signs of infection have appeared.

Myxomatosis was introduced to Australia in 1950 to reduce pest rabbit numbers.  The virus initially reduced the wild rabbit population by 95% but since then resistance to the virus has increased and less deadly strains of the virus have emerged. Pet rabbits do not possess any resistance to Myxomatosis and mortality rates are between 96-100%.

What are the signs of Myxomatosis?

Infected rabbits will show signs from 3-21 days after being exposed to the virus. They include:

  • Swelling of the skin around the eyes, ears, occasionally the lips and nostrils and the skin around the anus and genital area
  • Lethargy
  • Disinterest in food
  • Fever
  • Eye and nasal discharge
  • Breathing difficulties

In some rabbits with a very nasty strain of virus, minimal symptoms may be noted before sudden death occurs.

Another rare symptom (in a much less common strain) causes a lower grade chronic disease and lower rate of fatal outcomes. It can result in lumps developing around the ears and face that will resolve on their own. These lumps are named myxomas and the disease virus was named after this lesion.

What should I do if my rabbit develops Myxomatosis?

It is important to separate any suspected diseased rabbits from other rabbits immediately and seek veterinary help. Unfortunately, because of the lack of an effective treatment and the high mortality rate, it is often recommended to humanely euthanise the affected rabbit to avoid suffering a drawn out and painful death. The disease is not transmissible to any other species (cats, dogs and humans, etc).

If a rabbit does die or needs to be euthanised, it is extremely important to disinfect the rabbit’s environment as thoroughly as possible because the virus can survive for long periods in the environment. This would mean:

  • Discarding straw and hay from a hutch
  • Emptying the hutch of any other rabbits
  • Cleaning and disinfecting (with bleach) the feeding bowls and drinking bottles
  • Companion rabbits should be isolated for 3 weeks to ensure they do not develop disease
  • Disinfecting the hutch (with bleach) as effectively as possible is mandatory if it is being reused
  • It would be advisable to not reintroduce new rabbits into the environment for a minimum of four months

How do I prevent my rabbits getting the disease?

The best way to prevent rabbits from getting the disease is to reduce the possibility of contact with the insects that will transmit it to your home environment. Keeping rabbits inside is the best way to reduce the chances of them being bitten. If this is not practical or possible, covering outside enclosures with mosquito netting is advisable. Use of other insect repellents such as pest strips, surface sprays, mosquito coils, etc. may help with this.

Mosquitos and flies are more active at dusk and dawn, so having rabbits confined at these times will help reduce risk. Treating your other domestic pets with flea products will help reduce flea populations and eliminate the transmission risks from fleas. Rabbits can be treated with some (but not all) topical cat and dog flea treatments safely and effectively. Please consult your veterinary surgery for advice on the best products to use

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