Rabbit Vaccinations- Myxomatosis and Viral Haemorrhagic Disease

Since I last posted in 2012 (yes really, 4 years ago!), rabbit vaccinations have taken another leap forward. Unfortunately our bunny friends are the favourite target of virus bio-control worldwide, and myxomatosis and viral haemorrhagic disease are still as much us as ever. In fact, VHD now has a news strain – VHD2 which I did a video blog on last year.

As you’ll see, they’re common, easy to catch, hard to treat and almost invariably fatal. The good news is the vaccines are excellent! Here’s a brief recap on what these diseases are, and how to protect against them.

Myxomatosis

Myxomatosis is a highly contagious viral condition of rabbits caused by the myxoma virus, a member of the poxvirus group. It was first recognised nearly 70 years ago in the UK, and is a major cause of death in the wild rabbit population. It’s usually spread by insects, particularly by the rabbit flea, but is also very contagious through direct and indirect contact such as unwashed hands.

It can be:

  • acute- death within 14 days of infection
  • chronic- nodules forming on the nose, paws and ears with death in 50% of cases within 40 days
  • specialised- usually only seen in Angoras

There is also a respiratory variant seen in farmed rabbits which is induced by the classical form, and is more difficult to diagnose as we often don’t see any signs.

Signs after infection are a high temperature within 48 hours, and illness lasting 11-18 days. During the illness phase we see pronounced swelling of the face and around the genitals. Eventually haemorrhages will kill the rabbit.

Control is through prevention of contact with the agents of spread and vaccination. Fly nets and fly repellent to prevent fly strike are recommended. There is an effective UK vaccine which protects the rabbit after a single injection for up to 12 months, but ut takes 3 weeks to become fully active after injection. Studies have shown that the vaccine is 100% effective at protecting rabbits from myxomatosis at this 3 week interval, whilst at 12 months post vaccination 25% of vaccinated rabbits exposed to myxomatosis showed mild signs, whilst 75% were still completely protected.

Treatment of myxomatosis is usually unsuccessful, requires hospitalisation and can be very expensive.

Viral Haemorrhagic Disease

Also known as: Haemorrhagic Viral Disease, Viral Haemorrhagic Disease, HVD, VHD, HDV, RHDV

This is a severe viral disease spread by direct contact with infected rabbits, or their secretions on “fomites” (inanimate abject carrying infection e.g. stones, grass etc.) Flies and other insects are an effective means of spread, usually when they rest on the conjunctiva around the eye.

Rabbits usually die within 2 days of infection with haemorrhages in the lungs and liver necrosis. Usually rabbits under 8 weeks are resistant, but older rabbits can develop one of three forms:

  • Peracute disease: fever and death within 36 hours of its onset.
  • Acute disease: dullness, anorexia, congestion of the palpebral conjunctiva, prostration, bloody nasal discharge, cyanosis, ocular discharge and epistaxis followed by death.
  • Subclinical infections: milder signs, jaundice, anorexia

Death rates are usually between 40% and 90%, but animals that recover usually develop jaundice, fever and die a few weeks later. There is no treatment.

As with myxomatosis, control is achieved through reduction in contact with flies and the wild rabbit population, and through vaccination. Vaccination is almost completely effective and protection lasts for 12 months. Protection against VHD can be administered in the same injection as myxopmatosis

Unfortunately, this is how you usually know your rabbit has VHD as it kills so quickly:

In the last 12 months, we have seen a development of VHD type 2. Our existing UK vaccines do not yet protect against this strain which has similar signs and fatality rates as described above. However we can import a vaccine from France; this needs to be administered 2 weeks after the myxomatosis/VHD1 vaccine.

Conclusion

VHD and myxomatosis are seriously nasty- they kill in most cases and are almost untreatable. They are easy to catch, very common, but (frustratingly) have excellent vaccines. Our recommendation is that if you keep pet rabbits, you should seriously consider vaccinating them.