A serious infection of the nervous system, usually transmitted in saliva from a bite by an infected animal
- Travel to Africa, Asia, and South and Central America is a risk factor
- Age, gender, and genetics are not significant factors
The rabies virus mainly affects animals but can be passed to humans by an animal bite or a lick over a break in the skin. After entering the wound, the virus can travel along nerves to the brain and cause potentially fatal inflammation. Immunization against the virus and prompt medical treatment give complete protection against the disease, but, if left untreated, about half of all people bitten by a rabid animal develop rabies and almost inevitably die.
Rabies is very rare in developed countries, although only a few, including the UK, Japan, and Australia, are completely free from the disease. Africa and many parts of Asia are high-risk areas. In developed countries, most cases are due to bites from bats, and worldwide most cases result from bites by dogs that have been infected by wild animals. Some animals infected with the rabies virus act aggressively and salivate excessively.
What are the symptoms?
An infected person may develop symptoms within 2–8 weeks of a bite, although the incubation period is very variable and the virus can lie dormant for months or longer before causing symptoms. Rabies usually starts with flu-like symptoms (see Influenza) that last for about 2–7 days, followed by:
Paralysis of face and throat muscles.
Painful throat spasms leading to an inability to drink and a fear of water.
Disorientation and agitation.
Loss of consciousness.
Paralysis of limbs.
Once symptoms have developed, the condition is usually fatal.
What might be done?
Wash all suspect animal bites immediately with soap and water. Seek medical advice without delay because treatment must be started at once to be effective. Treatment includes injections of rabies immunoglobulin (antibodies against the virus), followed by a course of rabies vaccine to simulate production of more antibodies. If possible, the animal that inflicted the bite should be quarantined and observed.
There is no cure once the symptoms have developed, but sedative drugs and painkillers may be given to help alleviate the symptoms. Diagnosis may not be obvious from the symptoms, and blood and saliva tests are usually carried out to confirm the presence of the virus.
Rabies can be prevented by a vaccine, which is recommended for people working with animals. It may also be advised for people travelling to or living in areas where rabies is endemic (see Travel immunizations).
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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