Rabies is a viral form of disease that can cause inflammation of the brain (encephalitis) in mammals and birds. It is a zoonotic disease meaning that it is transmitted by animals but can also affect humans, and it is normally transmitted through being bitten by an infected animal.
The symptoms can be very severe and it is normally fatal if prophylaxis is not administered before the victim shows signs of severe diseases. It is often associated with dogs, for which one of the main symptoms is foaming at the mouth. This is an accurate association as in fact 97% of all human infections come from dog bites. As such, anyone bitten by a stray dog that seems to be acting oddly or is foaming at the mouth, should seek the consultation of a doctor immediately. A doctor can identify the presence of the rabies virus by analysing saliva, skin samples and urine, though this is not 100% effective. Where possible the animal that caused the problem will also be checked over for rabies. In some cases the diagnosis will mistake the rabies for other causes of encephalitis.
The rabies virus will travel to the brain via the peripheral nerves. For humans it normally takes around a month for the symptoms to begin (the incubation period) and this will be dependent on the amount of time it takes for the virus to reach the central nervous system. At this point symptoms will begin to show and the administering of prophylaxis will become ineffective. It is normally then fatal within days.
The first signs of rabies are malaise (general tiredness), headaches and a fever. This is caused by the brain's swelling and sometimes pushing against the skull walls. This will then give way to acute pain, coupled with violent uncontrolled movements, depression and a fear of water (hydrophobia). The patient may then also experience symptoms of mania – which is characterised by hyperactivity, elevated mood, creativity and restlessness, and of lethargy which is characterised by tiredness and lack of interest. This will eventually lead to coma and then death, with the major cause of death normally being suffocation as the patient fails to breathe correctly.
Fortunately in 1885 Louis Pasteur and Emile Roux developed a vaccine which was developed from analysing infected rabbits. Here the virus was allowed to dry in the nerve tissue for five to ten days making it weak enough for the body to fight it off and develop antibodies. Since this time a new and more affordable vaccine has been developed using a purified chicken embryo cell. Widespread vaccination in the US has also fortunately managed to eliminate the rabies virus in dogs, while in the UK and Japan it has been eliminated in all land animals – though there is still concern about birds as carriers as well as some other air born animals. As a result the number of deaths caused by rabies has dropped to 1 to 2 a year in the US. Today the main source of concern in the US and UK are bat bites, which can also go unnoticed resulting in failure to treat the disease. Another problem is for those travelling abroad where the vaccine has not been widely administered and for those in other countries. Around the world rabies kills a total of around 55,000 people however, those mostly in Asia and Africa.
Should you find yourself bitten under any circumstances you should wash your wound with hot soapy water. This can help to remove particles of the virus and can also help treat other infections such as tetanus. If post-exposure prophylaxis (PEP) is administered within ten days of the bite then it is highly successful in preventing the disease. It is recommended for individuals who wake to discover a bat in the room, or who discover a bat in the room of a child or relative, should seek out prophylaxis. In some cases rabies can be successfully treated by induced coma should the patient miss the opportunity for prophylaxis to be used effectively.