RABIES – Is there a risk to my horse or myself?
”Live as if you were to die tomorrow. Learn as if you were to live forever” – Mahatma Gandhi
Rabies is a virus that can infect any warm-blooded animal, including horses and humans. It is spread by saliva in bite or scratch wounds, although signs may not appear for months or years. In horses, the signs can vary from aggression through to just lameness or colic, although a wide range of signs mean that it is often hard to diagnose without a post-mortem. Humans can become infected from the saliva of an infected animal e.g. their horse, dog, wild animals, or other humans.
Once signs appear, there is no treatment and it is nearly always fatal, although there is a preventative course of injections for humans who have been bitten/scratched. By far the best option though is to avoid infection and to have vaccinations if in an at-risk situation.
Rabies is caused by a Lyssavirus (a rhabdovirus), which can infect any mammal including humans, horses, dogs, and other warm-blooded pets, and is nearly always fatal.
In countries where it is endemic in the wildlife (i.e. it survives in populations of wild mammals such as foxes, weasels, badgers, and bats) control measures are usually put into place to limit infection and these include vaccination for animals and at-risk humans. Although some countries are Rabies free (e.g. UK, Australasia, some European countries), there is always the risk that the disease could be brought into the country by a travelling pet or smuggled animal, or even by a human who has been bitten while overseas.
How can my horse or I get infected?
The most common way for any animal to get rabies is from a bite, as the virus is transmitted in saliva. However, it is also possible to get infected via saliva entering a break in the skin (either an existing wound or from a scratch from an animal) or from saliva contacting the mucous membranes e.g. in the eyes or mouth. If you are in a country that is ‘rabies-free’, then the chances of a human or horse getting infected are very slim. The most likely cause would be an infected animal brought in from another country without being vaccinated/quarantined e.g. a pet dog biting you or your horse.
Even in some countries where there is rabies in wild populations of animals (e.g. North America), rabies in humans and horses is rare, although it is more common in species such as cats and dogs that can contact wildlife. This is partly due to the control measures put in place for prevention (see below). However, if you are travelling to/through, or working in, countries with known rabies infections, then the risk of infection is increased and it is important to read up about rabies before travelling.
The incubation period (time between the bite/scratch and the signs of the disease) can vary from days to years, depending on various things such as where the bite occurred, the strain of the virus, and other factors. This means that you may not even notice when your dog or horse first became infected, as the wound may have healed long ago, and it is also the reason why quarantine periods are so long for unvaccinated animals moving between countries.
What are the signs in horses?
The virus travels from the site of the wound up the nerves to the spinal cord and then to the brain. Therefore many of the signs are similar to other diseases that affect the nervous system and brain of animals.
Some species show signs of the ‘furious form’ of rabies, with severe aggression and attacking of other animals and humans – this is the type that occurs in dogs and is the favourite type demonstrated in the movies. Other species show signs of the ‘dumb form’ of rabies, with signs of depression leading to tremors, difficulty swallowing and paralysis – this is the type that is common in ruminants such as cattle or sheep.
Horses can show signs of both the furious and dumb form, and many of the signs are easy to confuse with other conditions. However, just about all cases are fatal, with the horse usually dying within days of the first signs. Some of the signs that may occur include: excitement, viciousness, self-mutilation, incoordination, seizures, paralysis, excessive reactions to things, lameness, choke, colic, problems swallowing and drooling, loss of appetite and depression. Not all of these signs occur in all horses, and the only guaranteed way of diagnosing rabies is by tests done on post-mortem. However, the most common signs are neurological ones, so unusual behaviour should be investigated.
Can it be treated?
First aid involves cleaning wounds thoroughly, as well as rinsing eyes etc. exposed to saliva from suspected rabid animals. If there is any suspicion of a rabid animal being involved then the incident should then be reported immediately.
There is currently no treatment for rabies in animals, and no treatment in humans once the signs have appeared. If a human gets bitten by a rabid animal (or one suspected of being rabid) then they are given various injections: firstly, an injection of rabies immunoglobulin as soon as possible after the bite (to try to prevent the virus spreading), followed by a series of vaccinations (usually 2-5, depending on whether the human has been vaccinated before).
Can it be prevented?
Animals such as horses and dogs, as well as humans, can be vaccinated against rabies if they live (or work) in an area where rabies is likely to be a risk, or if they are travelling to or through such countries. In horses, there is often an initial course of several injections, followed by an annual booster.
There are specific regulations controlling the transport of animals in and out of the UK, as well as when entering various other countries and it is VERY important to follow these regulations precisely, particularly the timing of vaccinations. People sometimes think it is ‘ok’ to take their pet on holiday or bring it back, or a stray that they found, without following all the steps involved but saving time and money could cost you and other people/animals their lives. The current UK regulations can be found at: https://www.gov.uk/take-pet-abroad/rabies-vaccination-boosters-and-blood-tests (website accessed June, 2015).
When travelling or working in countries with rabies it is always wise to avoid contact with wild animals, as well as unknown pets and other domestic animals. Infected animals may show unusual behaviour (e.g. nocturnal animals about during daylight) but may also act normally. Wild animals with rabies can lose their fear of humans and appear friendly or ‘tame’, increasing the risk of a human getting bitten (particularly children, who may not realise this is abnormal).
To sum up:
- Can my horse get rabies from an infected animal? Yes
- Can I catch rabies from my horse if it is infected? Yes
- Is there a high risk of my horse or I getting infected in the UK? No
- Does travelling through or to some countries increase the risk? Yes
- Are the signs of rabies in horses always obvious? No
- Does vaccination protect horses and humans from rabies? Yes
- If a wild animal acts friendly, could it be rabies? Yes
- It is safe to avoid border control if my dog, cat, or horse looks healthy? No
Rabies is extremely unlikely to occur in countries such as the UK, particularly if people follow border control regulations. However, it is very important to know how rabies is spread in order to limit the risk both home and abroad. Rabies is a notifiable disease in the UK, therefore any suspicion of infection should be reported as soon as possible in order to prevent disease and to control outbreaks.