Gemma Gaitskell
Dr Gemma Gaitskell (BVetMed MSc MRCVS, Royal Veterinary College, London)
 
Rabies Vaccine

Rabies is a very serious disease which has been eradicated from the United Kingdom so is unlikely to be a threat to the majority of dogs who live there. It is extremely severe and mostly fatal.

However, if you are thinking of travelling outside the United Kingdom with your dog it will require vaccination. When travelling abroad in areas where rabies is present extreme care should be taken and touching dogs and wildlife should be avoided.

What is Rabies?

Rabies is an acute, extremely severe disease caused by types of lyssaviruses that belongs to the Rhabdovirus family. It is a disease that can affect any type of mammal, including humans, although canines appear to be particularly susceptible to it. Rabies is a disease that is endemic (native) to many parts of the world. The UK, Australia and New Zealand are free from rabies. However, the Department for Environment, Food and Rural Affairs (DEFRA) notes that although rare, bat lyssaviruses are present in the UK bat population. In the UK, rabies was eradicated from all other animals apart from bats in 1922.

Rabies is a dangerous disease that is almost always fatal once clinical signs appear. It kills over 30,000 people worldwide every year. It is the most fatal infectious disease currently known to man. The rabies virus is able to survive in the environment if the conditions are favourable for it. It survives well at low temperatures and with minimal exposure to light.

How Does Rabies Spread?

Rabies Virus

The Rabies Virus

Rabies is transmitted through saliva of an infected animal when one animal bites another. It is also present in tears. The amount of time it takes for the clinical signs of rabies to develop can be very variable, ranging from around 10 days to up to 12 months.

This means that the presence of rabies virus infection may not be immediately apparent making the virus all the more dangerous. This time is thought to be dependent on the location of the bite. The further away the bite is from the central nervous system (spinal cord and brain) the longer the virus takes to incubate and produce clinical signs.

The rabies virus replicates in muscle tissue and then gradually travels via the nervous system until it finally reaches the brain. Here it continues to replicate further and travels to infect the cornea of the eye and salivary glands, which is how the virus comes to be present in saliva and tears. In addition to being spread through bites, rabies can also be spread if saliva from an infected animal comes into contact with an open wound or any type of mucous membrane, such as the mouth, eyes, nose and ears.

When are Dogs Most at Risk from Rabies?

Dogs from the UK are most at risk from rabies if they are travelling abroad with their owners. As the virus has long been eradicated and is not endemic in dogs in the UK they are unlikely to have any natural immunity against it. There are different requirements for pet travel and entry into the UK depending on where the dog is coming from. The Pet Travel Scheme means that vaccinated animals can enter the UK without being quarantined from certain destinations, making travel, particularly within the EU, much easier for dog owners who wish to take their pets abroad on holiday with them.

Are People at Risk of Rabies?

Rabies is a zoonotic disease and this means that humans who are also mammals can be infected. 99% of human rabies cases are from dog bites. It is therefore very important to seek medical attention if you are bitten by an animal in a country where the disease is endemic or if you are bitten or scratched by a bat in the UK. Vaccination can also be very effective after a person is bitten, but only for a limited period of time before the virus establishes itself in the body.

There are vaccines against rabies available for humans who are in areas where they could be at risk of being infected with rabies. The vaccination course can be given prior to exposure to the virus, but must also be given after if a person is thought to have been at risk from infection. Even if a person is not vaccinated prior to being infected with rabies preventative methods, such as wound disinfection and vaccination are almost always effective.

Symptoms of Rabies in Dogs

Symptoms of Rabies

Rabies causes progressive clinical signs depending on the stage of the disease. There are two different types of presentations of the clinical signs – the dumb or paralytic form and the furious form (mad-dog syndrome). The dumb form may follow the furious form or simply appear alone.

Dogs can develop either or both, and despite the common misconception that dogs become overly aggressive when infected (the furious form) they are most commonly infected with the dumb form of the virus. The first signs to become apparent in a dog infected with rabies are:

  • Behavioural changes – increased cautiousness or boldness
  • Excessive attention seeking and trying to lick owners
  • An increase in sensitivity to noise and/or light with visibly dilated pupils
  • A high temperature

These signs are often followed by:

  • Increased levels of aggression, including attacking other animals, humans or objects – furious form
  • A glazed expression in the eyes
  • A droopy mouth and excessive salivation
  • Abnormal itchiness.
  • Excessive thirst and drinking

The signs often seen in the last stages of rabies are:

  • Frothing at the mouth
  • Loss of coordination and muscle weakness, particularly in the legs and tail
  • Sleepy looking eyes with droopy eyelids
  • Problems swallowing
  • More generalised paralysis leading to convulsions and eventually coma and death

In reality clinical diagnosis of rabies can be complicated, especially in countries where the disease is uncommon as early stages of the disease can easily be confused with other diseases and may not be considered if history of contact with an infected animal is not known. A definitive diagnosis can only be made by testing brain tissue from a dead animal. Once a dog has developed clinical signs of rabies it will usually die within 3-10 days and there is no known treatment.

Rabies is a notifiable disease, so if it is suspected in a dog or any other animal it must be reported to the Animal and Plant Health Agency (APHA) by the veterinarian treating them.

Can Rabies in Dogs Be Treated?

There is no known treatment once a dog has developed clinical signs of rabies. If there is a suspicion that a dog is infected with rabies, it should be isolated immediately. The possibility of infection should be reported to the AHVLA and a Veterinary Inspector will then make the necessary decisions on how to act, depending on their level of certainty of infection. These decisions are based on the country of origin and welfare of the dog and may include quarantine and isolation with observation or euthanasia. Any dogs or other animals, which may have been in contact with an infected dog will also need to be considered.

Preventing Rabies in Dogs

Dachshund Vaccinated

In countries where rabies is endemic dogs should be vaccinated yearly. Dogs who live in the UK are not at risk of being infected with rabies and it is highly unlikely they will ever be exposed to the disease. However, if you wish to take your dog abroad, out of the UK under the Pet Travel Scheme it should be vaccinated and you should seek advice from your veterinarian as to vaccination timings and the necessary paperwork.

Another important aspect of rabies control in dogs in countries where the virus is endemic is controlling the presence of the virus in stray dogs and wildlife. Some methods used to do this have included oral vaccines, left in baits for wildlife, which has allowed the elimination of the disease from most of Western Europe and also mass vaccination programmes in stray dogs.

The Importance of Vaccination Against Rabies

Vaccination forms the backbone in the fight against rabies and its elimination. Although rabies in dogs has been eliminated from the UK, owners must vaccinate their pets if they wish to travel with them. The rules and regulations vary depending on the destination of travel. People should also take care with dogs and wildlife when travelling to countries where rabies is present, as the disease is severe and if preventative measures are not taken in time, almost certain to cause death.

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