Rabbit calicivirus (Rabbit Haemorrhagic Disease Virus, or RHDV*) is one of two viruses introduced into Australia to control wild rabbit populations (the other being myxomatosis). It causes extreme internal haemorrhaging and can lead to death within 1-2 days.

The first strain of RHDV was introduced in to the wild rabbit populations of Australia in 1995 from the Czech Republic, and has since diversified and evolved. As a result, many wild rabbits have developed immunity to calicivirus, with a number of non-pathogenic strains giving cross protection against the pathogenic strains.

RHDV strains currently present in Australia:

• RHDV 1 – Original virus released in 1995 (also known at the Czech strain).
• RHDV1A – Variant of type 1 isolated in Sydney in 2014.
• RHDV1 K5 – Variant of type 1 found in Korea (Australian release planned in March 2017).
• RHDV 2 – First recorded in Europe in 2010, and in Australia in 2015.
• RCV A1 – Non-pathogenic virus present in wild populations.

In Australia, we are currently only able to vaccinate against RHDV 1 with the Cylap® RCD Vaccine.

*You may often see rabbit calicivirus referred to as RHD (Rabbit Haemorrhagic Disease), RCV (Rabbit Calicivirus), and RCD (Rabbit Calicivirus Disease) depending on which country you’re in.

Symptoms of RHDV1 (and variants) include:

• Depression
• Lethargy
• Neurological problems
• Anorexia

What is the Korean Strain (RHDV1 K5)?

In 2014, the Australian government investigated a number of calicivirus strains not present in Australia, in an attempt to find one that would be effective against the wild rabbits that have immunity to the current Australian strains, particularly the non-pathogenic RCV-A1. They found that the Korean RHDV1 K5 was the most effective.

On the 29^th April 2016, the Australian government announced that RHDV1 K5 was approved as a Restricted Chemical Product by the Australian Pesticides and Veterinary Medicine Authority (APVMA) and would be scheduled for a controlled release. Read the media release HERE.

RHDV1 K5 is a variant of the RHDV1 virus released in 1995. The existing RHDV1 vaccine (Cylap®) is hoped to be effective against RHDV1 K5. An initial study completed by the NSW Department of Primary Industries compared the mortality of a small number of vaccinated and unvaccinated rabbits that were subsequently infected with a high dose of RHDV1 K5. All of the rabbits vaccinated with the currently available vaccine survived and did not show any clinical signs; none of the unvaccinated rabbits survived. But while the vaccine is expected to be effective, suspicious deaths, particularly in vaccinated rabbits, should be investigated.

Read more on the RHDV1 K5 roll out HERE, or contact your local state and territory representatives:

What is RHDV2?

There has been some confusion between the new variant RHDV1 K5 (to be released in March 2017) and the discovery of RHDV2 in 2015, but these are completely different forms of the virus.

RHDV2 is a calici-like virus that was discovered in Europe in 2010, and is significantly different to previously known strains, including those in Australia. This new form has been found to cause death in a small percentage of rabbits previously vaccinated with the Cylap® vaccine. It is also able to infect rabbits at a younger age (as young as 4 weeks old), and some rabbits experience a more prolonged death (weeks vs days) than previously seen in other forms of calicivirus.

The Australian government rejected the use of RHDV2 based on information from European studies; however an Australian strain was discovered in wild and farmed rabbits in 2015. It is not yet known whether it is the same as the European strain, or just a relative. As such, we do not have enough information as to how it will affect vaccinated rabbits, and what studies are available show erratic results.

The Australian RHDV2 was first detected in the ACT, and subsequently in New South Wales, Victoria, South Australia, Northern Territory, Tasmania, and Western Australia.

Clinical signs of RHDV2 differ from other strains, and include:

• Pyrexia
• Seizures
• Hypoglycaemia
• Anaemia
• Kidney and liver problems
• Death

How Can I Protect My Rabbit?

The pathogenic strains of calicivirus are considered highly contagious and can be transmitted via: direct contact with infected rabbits; fomites (objects or materials that can carry the virus e.g. bedding, clothing etc.); and other animals/insects (birds, flies, fleas etc.).

Vaccination is still the best way to protect your rabbits from all forms of calicivirus. The Australian Veterinary Association has recently revised their recommended vaccination protocols as follows:

Kittens: 4 weeks, 8 weeks, and 12 weeks of age; then every 6 months for life.

Adults: 2 vaccinations, 4 weeks apart; then every 6 months for life.

Please be aware that this protocol is considered “off-label” – Cylap® is not registered for 6-monthly use or in rabbits younger than 10 weeks, and is not registered for use against RHDV2. Please make sure to discuss this with your veterinarian before administering.

Vaccinations should only be administered to healthy animals, and like all medications, carry the risk of side effects. These are usually minor, however, with extreme reactions being very rare. Pet Doctor will be implementing the new vaccination protocols as recommended by the AVA, but we greatly appreciate feedback and encourage you to discuss the risks/benefits with your veterinarian. These protocols may change as more information becomes available.

Other forms of prevention include:

• Insect screens around your rabbit(s) enclosure to keep our flies and other insects.
• Lots of disinfection – of people and equipment. Especially if there is movement between different locations (to and from shows, the vet etc.)
• Showering between visiting different rabbit colonies.
• Protect against fleas by using a preventative, such as Revolution.

We’re finally starting to see some warmer weather and most of us can’t wait to get outside – including our pets! While this is certainly a good thing – more time outside leads to better enrichment and exercise – it does come with its risks. While parasites are commonly seen by our vets all year-round, the increased warmth brings nasty internal and external parasites out in force. As our pets spend more time outside, they become increasingly at risk of becoming infested if not on a suitable preventative.

Which Parasites Concern My Pet?

Fleas, Ticks & Mites

Fleas, ticks, and mites are the most common external parasites found on dogs and cats, but they can also affect birds and pocket pets (guinea pigs, rabbits, mice etc.). More than just being annoying, they can be extremely contagious and cause disease and discomfort for animals – and people!

Did you know it can take as little as 7 seconds for flea pupae to hatch and jump onto a passing animal? They feed on blood and can quickly pass from animal to animal (and will even bite people given half a chance). One adult female flea can lay thousands of eggs in her life-time, meaning that the fleas you see crawling on your pet are about 5% of your infestation – 95% of the problem are the eggs and larval stages that live in the environment (i.e. your home). Read more…

Fleas can cause your pet to experience allergic reactions, skin irritation, and intense itching. They also transmit tapeworms (Dipylidium caninum). Luckily, fleas are simple to prevent and control when using monthly preventatives (e.g. Revolution, Frontline Plus, Nexgard) and surface sprays.

The biggest concern with ticks is the variety of diseases that they carry and transmit to both pets and humans. Lyme disease is one of the more common of these, with symptoms including fever, inflammation, and lameness. Other diseases include typhus, fever, and tick paralysis. In South Australia we don’t usually see paralysis ticks (Ixodes holocyclus), but they are common in the Eastern states so it’s important that your pet is on a tick prevention when travelling and/or camping. It’s also important to check your pets daily for any potential stow-aways. Read more on how to check for ticks…

Heartworm

Heartworm disease is an extremely serious condition and can be transmitted to dogs and cats via mosquito bite. These worms can infest and damage your pet’s heart and lungs and can be ultimately fatal if not treated early enough. Prevention is key to keeping your pet safe, and preventatives are easy and safe to use. Read more…

Intestinal Parasites

Regular worming is extremely important, but is often overlooked. Puppies and kittens are usually born with worms, contracted in-utero or via their mother’s milk, and should be dewormed every two weeks until 12 weeks of age. After this age, deworming should be done every three months for the rest of their life.

In Australia, dogs and cats can get infected with hookworms, roundworms, whip worm and tapeworm.  The microscopic eggs and larvae can end up on pet’s feet from anywhere, and then they become infected when they lick and clean their feet. If your dog licks their bottom and then licks your or your child, or if your child pets your dog and doesn’t wash their hands, he or she can become infected with these parasites.

Cats get infected with hookworms, round worms and tapeworms by eating prey they’ve caught.  Even indoor cats can have worms, if they ingest things like geckos, mice, insects, or fleas. Up to 50% of dogs and cats are thought to be carriers of gastrointestinal parasites.

Vaccinations are an essential part of keeping your pets happy and healthy. Vaccines help prevent the spread of many deadly and highly contagious diseases such as parvovirus, distemper, and hepatitis. Though there is much debate about the need for annual vaccination and how many your pet needs, most veterinarians agree that vaccines are essential to your pet’s health.

Understanding Vaccines

Vaccines help prepare the body’s immune system to fight of invading disease-causing pathogens. They contain antigens that, when introduced in to the body, trick the immune system into creating antibodies so that, if your pet is ever exposed to the real disease, the immune system now recognises and is prepared to fight off or reduce the severity of the illness. Puppies have a natural immunity which they acquire through their mother’s milk, however this immunity wears off over time so pups need vaccinations to help boost their immune system.

The Vaccination Guideline Group (VGG) of the World Small Animal Veterinary Association (WSAVA) recommends that vaccines be defined as core, non core or not recommended, and our veterinarians follow these guidelines.

Core Vaccinations

Core vaccines should be administered to all animals to protect them against severe, life-threatening diseases that have a global distribution.

Dogs: (C3) canine distemper virus, canine adenovirus (hepatitis), and canine parvovirus.

• Parvovirus: highly contagious disease contracted through contact with infected animals and faeces; attacks the intestinal lining and causes severe vomiting and diarrhoea which can lead to extreme dehydration and death. Doberman and Rotteweilers are particularly susceptible.
• Distemper: highly contagious, with no cure; mostly affects puppies and attacks multiple systems in the body, including the respiratory and nervous systems.
• Hepatitis: highly infections, contracted through contact with infected dogs and bodily fluids (urine, faeces, saliva etc.); infects the liver and kidneys and can lead to death.

Cats: (F3) feline panleukopenia virus, feline calicivirus and feline herpesvirus.

• Panleukopenia: also known as “feline parvovirus”, highly contagious and can be fatal. Contracted through contact with infected cats and bodily fluids, attacks the intestinal tract and severely suppresses the immune system.
• Calicivirus: highly contagious respiratory disease, spread through contact with infected eye, nasal, and oral discharges; along with feline herpesvirus, one of the most common causes of “cat flu”. Kittens, older cats, and immunosuppressed cats are at the greatest risk; most often seen in stray cats, shelters, and environments with overcrowding.
• Herpes: highly contagious upper respiratory disease; most common in kittens, older cats, and cats in stressed/overcrowded environments (e.g. animal shelters and multi-cat households). Once your cat becomes infected with the feline herpesvirus, they will have it for life and may experience recurrent episodes when stressed.

Non-core Vaccinations

Non-core vaccines are required by only those animals whose geographic location, local environment or lifestyle places them at risk of contracting specific infections.

Dogs: parainfluenza virus, Bordetella bronchiseptica, and Leptospira interrogans.

Cats: feline leukaemia virus, Chlamydia felis, and Bordetella bronchiseptica. Feline immunodeficiency virus (FIV) vaccines may also be classified in this group, however they’re strongly recommended for outdoor cats.

• Feline immunodeficiency virus: the feline equivalent to human immunodeficiency virus (HIV), FIV weakens/suppresses the immune system, leaving the body open to attack by other diseases. Transmitted through saliva (usually bite or scratch wounds from an infected cat), there is no treatment or cure for FIV – prevention is key here. Outdoor cats are most at risk as they are more likely to come in contact with feral cats who carry the disease.

Frequency of Vaccinations

When your pets are young, there is a standard schedule of vaccinations that need to be met during their first year of life. After this initial course, the core vaccinations should be administered every 1 – 3 years based on your veterinarian’s recommendations. This will be determined by your pet’s age, medical history, environment, and lifestyle.

If your dog is being placed in to a kennel (or kennelled regularly), or is in regular contact with other dogs (via shows, grooming, etc.), some of the non-core vaccinations will need to be kept up to date as well. Kennel cough vaccinations, especially, need to be given yearly regardless of your core-vaccination schedule.

Even if your pet’s vaccination schedule is every three years, an annual health check by a veterinarian is still essential to keep your pet healthy. When you think about it, an annual vet check is the equivalent of a human heading to the doctor’s office once every 5 – 7 years! A lot can happen in this time, and it’s important that we detect any problems early to provide effective treatment options and a healthier pet. Senior pets are recommended to see a veterinarian at least twice yearly because, like people, their health problems increase in severity and frequency with age.

If you’re concerned about over-vaccinating your pet, there is a test that can be done to determine whether a particular vaccination is necessary. These are called “titer tests”, and they measure the amount of antibodies in the body and can give us an idea of whether a booster may be needed or not. Ask your vet about titer testing at your next visit.

Are Vaccinations Safe?

Vaccinations mildly stimulate the body’s immune system in order to create antibodies to protect your pet from infectious diseases. As with any medical procedure, there is always a chance of side affects. Most pets show no ill-effects from vaccination, however some may experience mild symptoms ranging from soreness around the injection site, to mild fevers and allergic reactions. It’s important to talk to your vet about your pet’s medical history before it is vaccinated to reduce any risks. If you suspect your pet is experiencing an allergic reaction to a vaccine, contact your veterinarian immediately.

Keep in mind that vaccines have saved countless lives, and the risk of major side effects is much lower than the risk of contracting the actual diseases. Your vet is there to protect and look after your pet’s health and will not bring unnecessary risk to them while they are in their care. If you have any concerns or questions about your pet and their vaccination status, don’t hesitate to call and ask questions.

References: http://www.ava.com.au/policy/66-vaccination-dogs-and-cats