RABIES

PAPER-203

What is rabies?• Rabies is a serious illness. By the time the

symptoms of rabies have become apparent, it is generally too late to save the patient.

• Rabies is a virulent killer that can spread using any mammal species as a host

• Rabies is a viral infection spread via saliva.• If someone presents with rabies symptoms, it is

almost always fatal. • In countries where stray dogs are present in large

numbers, they are the biggest rabies threat.

What is rabies?

• Predominantly, in the US, rabies is spread by raccoons, coyotes, bats, skunks and foxes.

• Bats carrying rabies have been found in all 48 contiguous states.

• Dr. Joseph Lennox Pawan first discovered animal-to-human transmission of rabies in the vampire bat in Trinidad in 1932.

• It is now known that any mammal can harbor and transmit the virus.

• However, smaller mammals such as rodents very rarely become infected or transmit rabies.

The majority of human rabies cases are the result of a bite from a dog infected with the virus.

Symptoms of rabies

• The symptoms of rabies can present themselves just a few days after a bite, or they might take as long as 12 weeks.

• Some rare cases report a number of years between the bite and the onset of symptoms.

• The closer the bite is to your brain, the quicker the effects are likely to appear.

• When the initial symptoms of rabies occur, they can be similar to flu and last 2-12 days, becoming progressively stronger.

• From the early flu-like symptoms, the condition worsens and symptoms can include the following:

• Anxiety, Fever, Headache, Nausea, Confusion, Hyperactivity, Excess salivation, Fear of water (hydrophobia) due to difficulty in swallowing, Hallucinations, Priapism (permanent erection), Photophobia, Nightmares, Insomnia, Partial paralysis.

Causes of rabies• Rabies is a virus and, as mentioned, it predominantly spreads

by a bite from an infected animal.• However, it is also possible to become infected if saliva from

an infected animal gets into an open wound or through a mucous membrane, such as the eyes or mouth.

• Tests and diagnosis of rabies• At the time of a bite, there is no way to tell for sure whether

an animal is rabid, or whether it has infected you.• The doctor will suggest moving straight to treatment; there is

no benefit in waiting.

Rabies progression

• Rabies virus has a distinct cylindrical shape.• The rabies virus is an RNA virus in the rhabdovirus family. The virus has

five distinct stages:• 1. Incubation period: this can vary in length exceptionally, from days to

years• 2. Prodrome: early flu-like symptoms• 3. Acute neurologic period: neurological symptoms begin.• These can include hyperactivity, or paralysis, as well as rigid neck

muscles, involuntary muscle twitching, convulsions, hyperventilation and hypersalivation.

• Toward the end of this phase, breathing becomes rapid and inconsistent

Rabies progression• 4. Coma: unless attached to a ventilator, death will come within a

matter of hours• 5. Death: or, rarely, recovery.• The rabies virus can enter the peripheral nervous system directly and migrate

to the brain, or it can replicate within muscle tissue (safe from the host's immune system) and enter the nervous system through the neuromuscular junctions.

• Once within the nervous system, the virus produces acute inflammation of the brain, swiftly causing coma followed by death.