Define rabies and hydrophobia. What are the types of rabies vaccine? Write down the merits and demerits of cell culture vaccine.

Q. 46. Define rabies and hydrophobia. What are the types of rabies vaccine? Write down the merits and demerits of cell culture vaccine.
 Rabies is an acute highly fatal virus infection caused  by a rhabdo virus  which primarily infects the central nervous tissue and salivary gland of a wide range of mammals and most frequently transmitted to man by saliva through bites or licks which produces fatal encephalitis in man.
 Hydrophobia :- Rabies in man is called hydrophobia (means fear of water). It is the diseased condition is man caused by bite of a rabid animal. (i, e rabies in man).
 Types of rabies vaccine :-
1. Nervous tissue vaccines – (NTV)
(i) Inactivated sheep brain vaccine (sample vaccine).
2. Cell culture vaccine
(i) Human diploid cell strain vaccine (HDCSV)
(ii) Purified chick embryo cell vaccine (PCEC)
(iii) Purified vero cell rabies vaccine (PVRV).
 Merits of cell culture vaccine :-
1. More potent
2. Safest
3. Free of this risk of producing CNS complications.
 Demerits of cell culture vaccine :-
1. Very costly to prepare
2. Preservation is also expensive, the vaccine should be preserved in freeze- dried state.