Rabies

What is Rabies?

Rabies is a viral disease that infects domestic and wild animals and is transmitted to humans through close contact with infected saliva, such as through bites and scratches. Once symptoms of rabies develop, the disease will nearly always result in certain death.  Very few humans have survived rabies.

How do you get Rabies?

Rabies is transmitted to humans through close contact with the saliva of an infected animal. Most human infections result from the bite of an infected dog or cat. Several kinds of bats may also transmit rabies. It is very rare that humans become infected with rabies from wild monkeys, foxes, raccoons, skunks, jackals and wolves. Livestock, horses and deer can also become infected with rabies and potentially transmit the virus to other animals or people, however, this rarely occurs.

Susceptibility and Resistance

Humans are generally more resistant to infection with the rabies virus after exposure than some other mammals.  Nevertheless, all first aid and preventative measures should be followed since the illness, if acquired, is almost universally fatal.

Incubation Period

The incubation period for Rabies is 30-90 days.

What are the Symptoms?

The initial symptoms of rabies are flu-like, including fever, headache, and fatigue. The disease then progresses to involve the respiratory, gastrointestinal and/or central nervous system. In the critical stage of rabies, signs of hyperactivity or paralysis occur. Partial paralysis can eventually progress to complete paralysis, followed by coma. Spasms of swallowing muscles can occur when stimulated by the sight, sound, or perception of water, resulting in hydrophobia (fear of water). Delirium and convulsions can also develop. If the symptoms of rabies are allowed to occur, the disease will be fatal in nearly 100 percent of all cases, usually due to breathing failure due to paralysis. Death will occur during the first seven days of illness if not properly treated.

Preventative Measures

Rabies can be effectively prevented by avoiding direct contact with animals, especially by not touching or feeding any animals, including dogs and cats, and by closely supervising children around all animals.
 
There is an effective rabies vaccine.  Those who should consider a rabies vaccination include: veterinarians, long-term travellers and persons living in areas with a high risk of exposure; wildlife professionals, researchers, or adventure travellers who may be involved in activities that bring them into direct contact with bats, dogs, and other mammals. 

Specific prevention measures include the following:

After possible exposure to rabies:

Recent studies indicate that 4 doses of a cell-derived vaccine(a human diploid cell vaccine [HDCV] or a purified chick embryo cell vaccine [PCECV]in combination with rabies immune globulin (RIG) will generate adequate immuneresponses and that a 5th dose of vaccine does not enhance the immuneresponse.

If unvaccinated priorto exposure to rabies:

A combination of RIG and vaccine is recommended for bothbite and non-bite exposures. The reduced vaccination schedule with HDCV orPCECV vaccine should be administered intramuscularly, as follows:

·      First dose: as soon as possible after exposure(day 0);

·      Second dose: day #3;

·      Third dose: day #7; and

·      Fourth dose: day #14.

In addition, RIG should be injected into and around thewound site. Careful and vigorous cleaning of the wound is an importantcomponent of rabies prevention.

If previously vaccinatedprior to exposure to rabies:

A 2 dose regimen is recommended, as follows:

·      First dose: day 0; and

·      Second dose: day #3.

Use of RIG is not necessary and should not be used. Careful andvigorous cleaning of the wound is an important component of rabies prevention.

Before exposure to rabies:

For pre-exposurevaccination, a 3 doses regimen in recommended, as follows:

·      First dose: day 0;

·      Second dose: day # 7; and

·      Third dose: day # 21 or 28.

Special considerations:

For persons with compromised immune systems (e.g., HIV,organ transplant recipient, etc.) a 5-dose vaccination regimen with 1 dose ofRIG is recommended after exposure to rabies.

 Source: http://www.cdc.gov/rabies/resources/acip_recommendations.html

Animal vaccination, particularly of stray dogs, can eliminate the transmission of rabies to humans and other animals. Vaccination of domestic animals and some wildlife has led to significantly reduced occurrence of the disease in several developed and developing countries. 

Treatment

Rabies can be avoided if the wound of the bite or scratch is cleansed quickly and vigorously and then followed by the injection of rabies immune globulin (a preparation containing antibodies against rabies), plus a series of rabies vaccine injections immediately after the contact with a rabid animal. (See Preventative Measures)

If these precautions are taken promptly, onset of the symptoms of the disease (and nearly certain death) can be prevented in virtually 100 percent of exposures.  Once symptoms have developed, only the most heroic supportive therapy has managed to save a few people.

Vaccinations

Where Does It Commonly Occur?

Rabies can be found on every continent of the world. It is very difficult to predict where rabies may occur. Many countries are rabies-free due to vaccination of both domestic (e.g., dogs) and wild animals (e.g., bats, raccoons, etc.). The following areas are known to be free of rabies: the Caribbean Islands; Hong Kong; Japan; Kuwait; Qatar; Singapore; the United Arab Emirates; most European countries; and Australia.

Recent increases in human rabies deaths in South America and parts of Africa and Asia show that rabies could be re-emerging as a serious public health issue.

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