Rabies Virus

Ans. B. Purkinje cells of the cerebellum

The site in the brain that is a favored location for ischemic damage, rabies virus infestation, and toxic damage resulting from alcohol is the Purkinje cells in the cerebellum.

In chronic ischemia, the Purkinje cells undergo apoptosis (individual cell necrosis) and assume a shrunken, deeply eosinophilic cytoplasm with fading out of the nucleus (red neuron). The eosinophilic Negri inclusion body of rabies is located in the cytoplasm of the Purkinje cells. Alcohol has a direct toxic effect on Purkinje cells, resulting in cerebellar atrophy. 

The nucleus basalis of Meynert is associated with neuronal loss in Alzheimer’s disease. 

It is a bullet shaped virus with a single serotype. It is detected by immunofluoresence. 

The rabies virus is a neurotropic virus.

These viruses areenveloped and have a single stranded RNA genome with negative-sense. All transcription and replication events take place in the cytoplasm inside a specialized “virus factory“, the Negri body.

Ans. is ‘b’ i.e., 3 mm per hour

Rabies virus travels at a speed of 3mm/hour in the axoplasm.

• When rabies 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.
• p75NTR receptor, a protein that is found on the tips of peripheral neurons and known to bind a small molecule called NGF (for nerve growth factor). When NGF binds p75NTR, both are taken up into the neuron and move in acidic bubbles called “vesicles” toward the cell body. 
• The rabies virus can not only hijack the transport systems of the neuron, but might also manipulate the axonal transport machinery to facilitate its arrival at the cell body, and from there to the central nervous system at maximum speed.

Ans. is ‘a’ i.e., Natural rabies

Ans. is ‘d’ i.e., All

• Rabies virus is sensitive to

-Ethanol                                                     – Soap

– Iodine Preparations                                 – Detergents

– Quaternary ammonium Compound – Lipid Solvents such as ether, chloroform and acetone

• Rabies virus is inactivated by

-Phenol                                                       – UV irradiation

– Formalin                                                   – Sun Light

– Beta propiolactone (BPL)                              – Thermal inactivation (one hour at ⁵⁰⁰ C and 5 min at 60°C)

Ans. is ‘a’ i.e., Rabies is diagnosed by immunofluorescence

.  Diagnosis of rabies is usually made by the detection of rabies virus antigens by immunofluorescence.

.  Rabies does not cause life long immunity, in fact rabies infection cause death of all patients.

.  Rabies virus is of single serotype only.

.  Rabies Vaccines are killed inactivated vaccines

Ans. is ‘d’ i.e., They do not contain rabies virus antigen

Ans. is ‘d’ i.e., Produce infection that is almost fatal to humans

Rabies may present as                                                                                                     

.    Predominantly encephalitic disease – furious rabies

.    Paralytic illness – dumb rabies

In humans, about two – thirds suffer the encephalitic form and die within 7 days, the rest initially present as paralytic then develop encephalitis, and death may not occur for 2-3 weeks. Survival is exceedingly rare. About other options

.  There is no clinically significant viremia, so virus can not be isolated from the blood.

.  There are two types of strains –> Street virus and fixed virus, but they are antigenically similar.

.   Rabies virus can be transmitted from dog to man 3-4 days before the onset of clinical symptoms (not 4 weeks)

These cells are Negri bodies

Ans. is ‘d’ i.e., They do not contain rabies virus antigen