The facts about...

Rabies

The epidemiology of rabies

Rabies is a virus infection to which all mammals, including man, are susceptible. It causes an acute and almost invariably fatal infection of the brain. During the illness there are disturbances of behaviour which in some affected species, such as dogs, cause them to bite other animals and man. As rabies virus may be present in saliva, bites and licks can transmit the virus.

The incubation period in man is usually three to eight weeks, but may be as long as two years. Early symptoms may include numbness around the site of the bite, fever, headache, and general malaise. Later symptoms may include muscle spasms and hydrophobia.

In many parts of the world (but not in the British Isles, some other parts of Western Europe and Australasia) rabies is found in terrestrial wildlife species. In Asia, Africa and Central and South America it also commonly infects domesticated animals such as dogs and cats, but rabies in domestic animals is very rare in Europe and North America. Bites from any of these animals can transmit the infection to other domestic and farm animals, and man. Bats can also transmit rabies and rabies-like viruses.

In those parts of Western Europe where rabies is present in wildlife, it mainly infects foxes. Strenuous measures to control European fox rabies, for instance by vaccine left in baits, has reversed the movement of fox rabies towards the Channel ports, while strictly enforced quarantine regulations continue to prevent the introduction of other infected animals into Britain. In spite of its endemicity in foxes, rabies is rare in other animals in Western Europe, and extremely rare in man.

Human rabies

There is no rabies in terrestrial animals in the British Isles (we cannot be absolutely certain about bats), and the very rare human infections that have occurred in the UK have all been acquired elsewhere. There were 12 such cases between 1969 and 1996. Typically the patient had been bitten by a dog within the previous few weeks or months in an Asian or African country. Symptoms of human rabies can be greatly alleviated by sedation and drugs that relax muscles and assist respiration, but rabies in man is still almost always fatal. Except through corneal transplantation, transmission of the virus from a human case to another human is unknown and there is no evidence that infected patients are a hazard to their families or health care workers looking after them, though vaccine should be offered to these close contacts.

Prevention of human rabies

Most cases of rabies seem to have been preventable when the circumstances are reviewed. Either the exposure to a potentially rabid animal might have been avoided, or the bite or other wounds more promptly and thoroughly washed, or post-exposure immunisation more rapidly instituted. For those who through occupation and/or travel risk close contact with rabid animals, e.g. workers in quarantine facilities and veterinarians working abroad, pre-exposure rabies immunisation provides further protection. This involves two doses of vaccine given one month apart, or in the case of potential immediate exposure, three doses at 0, 7, and 28 days. If, subsequently, there is a suspected exposure to rabies, only a modified course of treatment is needed.

What should you do if bitten by an animal?

There is no risk of rabies from terrestrial animal bites in the British Isles. However, British travellers are sometimes bitten or severely scratched by dogs or other animals while abroad. In countries where rabies is endemic it is unwise to pet animals, and if animal bites or lacerations occur they should be taken seriously. Firstly, the wound should be flushed and thoroughly washed with soap and water or alcohol. Secondly, the name and address of the owner of the animal should be obtained and where possible the animal observed for 10 days to see if it begins to behave abnormally. Rabies infected dogs will almost invariably develop discernible disease and die within that interval. If necessary the assistance of local officials should be sought to ensure that the animal is observed. Thirdly, advice should be taken from a local doctor about further wound treatment and rabies immunisation. If the animal is wild or a stray and observation is impossible, and if the doctor knows that rabies occurs in the locality, they may advise immunisation. The rabies vaccines manufactured in Europe and North America are now widely available and safe, but expensive. If you are advised that the risk of rabies in the implicated animal is high and vaccine is unobtainable it will be necessary to travel to a larger centre or return to the UK for proper treatment.

If you are worried about an animal bite that you have sustained abroad, your general practitioner will advise you whether treatment is needed. His or her local Public Health Laboratory can provide doctors with current information on rabies throughout the world and suggest the circumstances in which immunisation is appropriate. If you are bitten by a bat, whether in the UK or abroad, you should seek specialist advice.

A final word of warning

An animal bite can spoil a trip abroad and give rise to needless anxiety. When you are abroad avoid unfamiliar animals and if you are travelling in a high risk area, e.g. trekking in Asia, keep your arms and legs covered. If you are bitten, promptly wash the wound, identify the animal and seek advice. If you are planning a walking or back-packing holiday in Asia, Africa or Central or South America, consider paying for immunisation against rabies before you go. It will not remove the need for treatment if you are bitten, but it will give you a large preliminary measure of protection.

Human rabies is a fatal but avoidable disease: learn how to avoid it.