Rabies ::

Rabies is a viral disease of the Central Nervous System that spreads through the bite of an infected warm-blooded animal. It is also known as 'Hydrophobia'. Transmission can also occur through saliva touching an open wound or mucous membranes.

Facts
1. About 60,000 people die annually of rabies, mostly in Asia and Africa.
2. In the U.S., one to three people die from rabies yearly.
3. Animal vaccinations and postexposure prophylaxis protocols have nearly eradicated rabies in the U.S.
4. More than 15 million people worldwide receive postexposure vaccination to prevent rabies every year.

Causes
✿ Rabies is caused by the rabies virus (lyssavirus Type-1).
✿ The virus infects the brain and ultimately leads to death.
✿ After being bitten by a rabid animal, the virus is deposited in the muscle and subcutaneous tissue.

Mode of Transmission
- Animal bite i.e. Dogs, cats, monkeys, cows, goat, sheep, horses.
- Licks (on abraded skin or abraded unabraded mucosa)
- Aerosols (Rabies infected bats)
- Person to person (rare but possible)
- Organ transplantation.

Incubation Period
✔ It depends on the site of the bite, severity of the bite, number of wounds, amount of virus injected.
✔ Commonly 3-8 weeks (minimum 9 days).

Symptoms can occur as fast as within the first week of the infection.

The early symptoms of rabies are very generalized, including weakness, fever, and headaches. Without a history of potential exposure to a rabid animal, these symptoms would not raise the suspicion of rabies as they are very similar to the common flu or other viral syndromes.

The disease can then take two forms:

1. With paralytic rabies (approximately 20% of cases), the patient's muscles slowly get paralyzed (usually starting at the bite site), is the less common form and ends incoma and death.
2. With furious rabies (about 80% of cases), the patient exhibits the classic symptoms of rabies, such as
• anxiety and confusion (The patient is often overly active.);
• encephalitis, causing hallucinations, confusion, and coma;
• hypersalivation;
• hydrophobia (fear and avoidance of water);
• difficulty swallowing.

Once the clinical signs of rabies occur, the disease is nearly always fatal.

How do physicians diagnose rabies?

In animals, rabies is diagnosed by detecting the virus in any affected part of the brain. This requires that the animal be euthanized. Testing a suspected animal will help avoid extensive testing in human contact (if the test is negative) and unnecessary treatments.

In humans, rabies is diagnosed by testing saliva, blood samples, spinal fluid, and skin samples. Multiple tests may be necessary. The tests rely on detecting proteins on the surface of the rabies virus, the detection of the genetic material of the virus, or demonstrating an antibody (immune) response to the virus.

What is the treatment for rabies?

Treatment is recommended if a healthcare professional thinks someone was exposed to a potentially rabid animal.

If the animal is a pet or farm animal that has no symptoms, the animal can be isolated and observed for 10 days. Wild animals that can be captured can be killed and tested for the virus. If the animal can't be found, it is best to consult the local health department.

The general pathway to determine postexposure prophylaxis (protective treatment) for rabies requires the following information:

• Bite: Did a bite occur, and where is the location of the bite? (Any skin penetration is considered a bite; although bites to the face and hands carry the highest risk, all bites need to be considered for prophylaxis.)
• Non-bite incident: Did the saliva touch an open wound or a mucous membrane?
• Animal risk factors: No cases of rabies infection have been reported in the U.S. from fully vaccinated domestic dogs or cats.
• Bats: Any contact with a bat that leads to a potential scratch, bite, or mucous membrane exposure to saliva needs to be evaluated. If prolonged exposure to a bat is discovered (sleeping in a room where a bat is found), postexposure prophylaxis needs to be considered.

As rabies is a fatal disease, it is often best to start the series of shots until further information is available.

A series of injections is given. The first is a rabies immune globulin that helps to prevent the virus from infecting the individual. Part of this immunization is given near the animal bite.

This is followed by four injections over the next two weeks. These are rabies vaccines to help the body fight the virus.