Rabies - rare but deadly infection

Rabies is extremely rare in the UK

Rabies is a serious infection of the nervous system that is caused by a virus which is usually transmitted by a bite from an infected animal.

The nature of the infection and the fact that it can lead to a lingering and painful death means that it is one of those rare conditions which strikes fear into humans.

Despite the paranoia which usually surrounds rabies, it is still an extremely rare disease in the UK and a case of suspected infection in Dundee is highly unusual.

The last known human case of rabies acquired in the UK was in 1902.

Bites from infected dogs can cause rabies

Between 1976, when rabies became a statutorily notifiable disease, and 2000, nine deaths from the condition were reported, seven of which were notified.

The death from rabies of one additional patient in 1996 was neither notified nor certified.

All of these rabies infections were acquired abroad.

Last year two Britons died from the condition but they were bitten by infected dogs while abroad.

In one of the cases, the infected man died five months after being bitten.

In recent years there have been two known cases of bats with rabies in the UK.

'Fear of water'

One was identified following the biting of a woman in Lancashire earlier this year. She did not contract the disease.

The other dated back to 1996 when tests carried out found one bat with the potential human killer.

Although bats are known to carry rabies, tests carried out on 3,000 of the creatures in the UK showed just two with the disease.

Rabid bats have been found in the UK

There have been three deaths from bites from rabid bats in Europe in the last 35 years, one in Finland and two in the Soviet Union.

The man being treated in Dundee is thought to have the rare form of the disease known as European Bat Lyssavirus (EBL) - a type known to exist in several north European countries.

Dr Dilip Nathwani, consultant physician in infectious disease, said: "This is a progressive neurological illness characterised by an ascending paralysis usually starting the feet and working upwards."

"I'm afraid that if the diagnosis of rabies is confirmed there is no cure for active disease and the prognosis is ultimately fatal."

More commonly, rabies is caused by a virus called rhabdovirus and is also known as hydrophobia.

The name hydrophobia, meaning "fear of water," was given to rabies because the ancient Greeks observed that rabid animals were averse to water.

Actually, the truth is that they cannot drink because of throat paralysis.

According to medical experts the infection starts with a "prodromal period" that usually lasts for one to four days.

Inflammation of the brain

Symptoms during this period can include fever, headache, malaise, muscle aches, loss of appetite, nausea, vomiting, sore throat, cough and fatigue.

Infected people may also experience a tingling or twitching sensation around the area of the animal bite.

The second stage begins with symptoms that look like those of an encephalitis or inflammation of the brain.

There may be fever with symptoms of irritability, excessive movements or agitation, confusion, hallucinations, aggressiveness, muscle spasms, abnormal postures, convulsions, weakness or paralysis and extreme sensitivity to bright lights, sounds, or touch.

Sufferers also experience an increased production of saliva or tears and there can also be an inability to speak as the vocal cords become paralyzed.

The last stages of rabies produce symptoms that reflect the infection's destruction of many important areas of the nervous system.

Neurological disability

There may be double vision, problems in moving facial muscles, abnormal movements of the diaphragm and muscles that control breathing and difficulty swallowing.

It is the difficulty in swallowing - combined with increased production of saliva - that leads to the "foaming at the mouth" usually associated with a rabies infection.

Finally, the person with a rabies infection can slip into a coma and stop breathing.

Without life support measures, death usually follows within four to 20 days after symptoms of rabies begin.

Most people infected with rabies die regardless of medical care, and those who survive usually have severe neurological disability.