Rabies

UNIVERSITY OF MARYLAND

BIOLOGY 302

RABIES

FAMILY: RHABDOVIRIDAE

Michael Green

4/17/2014

Rabies is a preventable viral disease to humans that is commonly transmitted through the bite of a rabid animal. It is a fatal disease, which is most of the time spread through an animal’s infected saliva entering the bloodstream of a human. This disease is important and interesting to humans because it occurs everywhere and kills at least 55,000 people per year. (World Health Organization, 2013)

Rabies virus belongs to the genus Lyssavirus within the family Rhabdoviridae. Lyssavirus includes 11 genotypes, of which type 1 represents the classic rabies virus. The RNA of this bullet-shaped virus encodes 5 proteins including the G glycoprotein which carries the main antigenic sites and the nucleocapsid (N) protein which encapsulates the viral genome and the RNA polymerase. (Rupprecht, 2013)

Rabies is caused by a rhabdovirus virus (Lyssavirus) which is transmitted in the saliva of an infected animal, usually a bat but almost any mammal will do. The virus goes to the muscle, where there is a very special synapse between the motor neuron and the muscle cell, called the neuromuscular junction. The ventral motor neuron releases acetylcholine as the neurotransmitter, and the muscle cell has acetylcholine receptors. The virus attaches itself to the acetylcholine receptor at the neuromuscular junction, and from there will hop over the synaptic cleft and into the motor neuron. There it will travel up the motor neuron axon using the retrograde transport mechanisms, divide in the motor neuron cell body, and then hop over the synaptic cleft to the neurons that are contacting the motor neuron. Again, it travels backwards up to that neuron’s cell body and the process is repeated. (Rupprecht, 2013)

The rabies virus will accumulate in the cerebral cortex, hippocampus, hypothalamus, and various parts of the brainstem. It is believed that the virus...