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Saturday 16 November 2019

Protect pet rabbits by vaccinating for viruses

All pet rabbits should be vaccinated against viruses
All pet rabbits should be vaccinated against viruses

Pete Wedderburn - Animal Doctor

The man on the phone was upset: he had just come in from his back garden, where he'd found one of his three pet rabbits lying cold and dead in the hutch.

The rabbit had been completely normal the previous evening, eating hay and behaving in her normal, active, friendly way. There was no sign of injuries: her body was untouched. What could have happened to her?

The two year old rabbit had been the mother of his "rabbit family": the "father", who was also a two year old rabbit, and their young 6 week old baby rabbit, seemed normal, but he was understandably worried about them.

As with other animals (and indeed humans) there are many possible causes of sudden death. The only way to be certain about what has happened is to carry out a full autopsy, and even then, sometimes it can be difficult to find a definitive cause.

I arranged for the rabbit's body to be transported to a veterinary laboratory for a full and detailed post mortem examination, and I asked the man to bring his other two rabbits in to see me immediately. It might take a couple of days for the full autopsy report, and meanwhile, it was important to do everything possible to protect the other two bunnies from the same outcome.

When I examined the remaining rabbits, there was not much to find: they were healthy, with no hint of a problem. There was just one issue: they had never been vaccinated.

Pet rabbits should be vaccinated against two viral diseases: Myxomatosis and Viral Haemorrhagic Disease. They should be given these vaccines as young rabbits, followed by an annual vaccination to ensure that they continue to be protected.

Both of these diseases are caused by viruses, which means that there is no effective treatment if they develop the conditions. The body has to try to fend off the viruses with its own immune system. If a rabbit is not vaccinated, there's little chance of being able to do this: the viruses overwhelm the rabbit's natural defences. If, however, vaccination is carried out, the body produces antibodies against the viruses, which means that if the rabbit is exposed to the real life disease, the vaccine-derived antibodies neutralise the virus before any harm is done.

At that early stage, the cause of the rabbit's death was still unknown, but I vaccinated the surviving rabbits anyway. I explained to the owner that if either of these lethal viruses was the cause, it might well be too late to vaccinate. It takes up to a week for a vaccine to confer protection. Since the two rabbits had been sharing a cage with the deceased rabbit, if a virus was the cause of death, it was likely that they had already been exposed. There is a so-called "incubation period" of 2 - 3 days between exposure to a virus and the onset of signs of illness. So there was a high risk that these two rabbits were already infected, in which case nothing could be done to stop the illness. It was still worth vaccinating, since all pet rabbits should be vaccinated anyway, and the vaccines would protect them if they encountered either virus at a later date.

I sent the rabbits home with their owner with strict instructions to monitor them carefully, and to let me know if there was any sign of them being unwell.

By that evening, the laboratory had released the initial report: the death of the rabbit had been caused by the Viral Haemorrhagic Disease virus. It would take a few more days for full virus isolation to be carried out, to work out whether this was the long-standing Type 1 virus, or the newer Type 2 variant. I passed on this gloomy news to the rabbit owner, and I explained to him that both of his remaining rabbits were under severe risk. Nothing more could be done, and it was just a case of hoping for the best. If they survived for a week, there was a good chance that they would be fine, because the vaccine would kick in by then. But the next week was going to be a high risk time.

The man was understandably very upset: his rabbits never went out of the fully-walled garden, and there could not have been any contact with any wild rabbits. How could they have picked up the virus?

I explained that the virus can survive in the environment, so as well as being passed on by direct animal-animal contact, it can be spread by birds, by rodents, and even on people's feet. The virus is very tough and can survive for many months in the environment. It's almost impossible to protect pet rabbits from being exposed in this way, which is why it's important to have them vaccinated.

The following day, the man found the adult male rabbit dead in the hutch. Again, an autopsy was organised, and it was no surprise when Viral Haemorrhagic Disease was confirmed. Then the virus isolation results came in, confirming the new variant of the virus, VHD2, which is rapidly spreading through Ireland's wild rabbit and hare population.

Next, the young rabbit went off her food, and we feared that she might also succumb. After a worrying week, she began to eat again, and she has gone on to thrive. Paradoxically, very young rabbits can cope with VHD more easily than unvaccinated adults.

Rabbit owners: are your pets vaccinated against VHD types 1 and 2? If not, talk to your vet about it: it's the only safe way.

Wexford People

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