Question

Rabies virus travels from the motor nerves innervating muscle tissue to the brain. This means that the rabies virus is using which direction of axonal transport? How do you know?

It can take 3 to 12 weeks for the virus to reach the brain. Other sources say it can take 30 to 50 days. If you were bit on the toe by a rabid raccoon, how long would you expect it to take for the virus to reach your brain? If a person is 5'2, use the speed of axonal transport to calculate a rate of travel. We will assume that the virus can find a motor neuron immediately, although it is actually likely that it would several days to a week for the virus to reach synaptic knobs of NMJs. Remember this is on your toe much farther from the brain than the hand or shoulder. Show your work.

Answer 1

Answer :

Rabbies lyssavirus , formely rabbies virus, is a neurotropic virus that causes rabies in humans and animals. Rabbies transmission can occur through the saliva of animals and less commonly through contact with human saliva. Rabbies lyssavirus , like many rhabdoviruses, has an extremely wide host range.

If bite is minor and doesn't break the skin , wash the area with soap and water.Apply over-the-counter antibiotic cream to the bite area and cover with a bandage. risk of contracting infections or diseasefrom this types of animal bite is low.

The rabies virus must move from the nerve endings to the nerve cell body where it can replicate. It then spreads into the end terminals of motor neurons innervating the muscles and travels along the neurons long axon fibers to the neuronal cell bodies. Virus infection occur in the brain and spinal cord if the bite by animal occured near to the head, as in hand or face rabies virus will travel and reach brain earlier. Since virus has to reach spinal cord and brain, it has to travel from the injured skin, tissue to the axonal terminals and towards the cell body and reaches the spinal cord and brain. Virus action is not at the place of injury, instead it's action are on the nervous system. So it has to go retrograde transport to reach central nervous system.

When the researchers meassured the speed of transport , they found that when rabbies virus is transported with p75NTR , it moves at about 8 centimeters ( a bit more than 3 inches) per day. Surprisingly , this is considerably faster ( by about 40 %) than the transport speed for NGF, the regular partner of p75NTR.

Researches found that rabies virus moves through neurones in retrograde manner towrads the spinal cord and brain. It moves at a speed of 8 cm per day. Here the the bite of rabeis carrying animal occured in feet. The hight of person is 5 feet 2 inch.

1 feet = 30.48 cm

so 5 feet = 5 * 30.48

= 152.4 cm

1 inch     = 2.5 cm

so 2 inch = 2.5 * 2

= 5cm

Total height = 152.4 + 5

= 157.4 cm.

Virus travels 8 cm per day. So the number of days virus need to travel 157.4cm = 157.4 / 8 = 19.67

20 days. So it will take 20 days to reach the brain.