Rabies

What is rabies?

Rabies (more technically known as Lyssavirus infection) is a viral infection that affects the nervous system, transmitted to humans in saliva when they are bitten by an infected animal.

Symptoms

The incubation period in rabies is very long – it’s usually between three weeks and two months before symptoms appear (and sometimes a matter of years).

During this time the virus is travelling through the nerves to establish itself in the brain, and it is very good at “hiding” from the immune system so that the body can’t build its defences against it.

When symptoms do appear, they reflect the fact that the infection is causing widespread inflammation in the brain. By this stage, it is very difficult to treat, so the risk of death is very high – few people have survived symptomatic rabies.

Symptoms develop in two phases:

• The early (or prodromal) phase includes fever, headache, nausea and vomiting, and numbness, pain and tingling around the wound. Stimulation of the autonomic nervous system can cause profuse salivation, drooling and watering of the eyes.
• In the second, neurological phase, symptoms include spasms of the throat and gullet, extreme thirst, hydrophobia (intense fear of water), anxiety, hallucinations, and manic behaviour (this is the stage in which animals become mad and bite. Eventually paralysis, confusion and coma may develop.

Causes and risk factors

Infected dogs are the most common cause of human infection worldwide, but in Western countries most cases are caused by bites from infected bats (although it is mainly carried by foxes). However the actual risk from being bitten by an infected animal is not high – only one in six of those bitten will develop symptoms if not treated.

Rabies infection is most common in Africa and parts of Asia. It's rare in Western countries. In 2002, a bat enthusiast in Scotland was the first person to die of UK-acquired rabies since 1902.

Treatment and recovery

If you are bitten by an animal, it’s vital to wash the wound thoroughly with plenty of water and if possible a soap or wound cleanser. Then you should see a doctor, especially if you are concerned the animal might have rabies.

The likelihood may be assessed by considering:

• The species of animal that bit the person.
• The frequency of rabies in the region.
• The behaviour of the animal (for example did it make an unprovoked attack?)

For the best chance of survival, treatment should be given as soon as possible after the bite.

Treatment involves injections of antibodies (immunoglobulins – immune system chemicals that fight the virus) followed by a rabies vaccination to stimulate production of more antibodies.

You should make sure you complete the course of vaccinations – although this means a total of three injections. The vaccine used now is much better than the older vaccine which used to be given in the stomach and was very painful.

Prevention is essential with rabies. To reduce the risk of infection, travellers are advised to avoid stray animals when visiting high-risk areas.

If you are staying for some time in an area where rabies is common, or if your job involves handling the rabies virus or potentially infected animals, you may want to consider getting vaccinated as a preventative measure.