Tuesday, March 15, 2011

Causes Of Chicken Pox(VARICELLA):

Chicken Pox(VARICELLA):
The causative agent of chicken pox is a virus called Varicella Zoster virus(V-Z virus) or HUman(alpha)herpes virus 3.
Mode Of Transmission:
Chicken pox is transmitted from person to person by droplet infection.The virus enters the upper respiratory tract commonly.Some times the disease spreads by contamination from the discharge from ruptured lesion of the skin.
Clinical features:
Clinical features include fever,apperance of the rash in the form of corps on the trunk,face, and the limbs.Within 24 hours the lesions become pustular(filled with pus).The pustules dry up in a few days to form scabs.
Incubation period:
Incubation period of the diseases is about 14 to 16 days.
Varicella Zoster immunoglobulin(VZ Ig) given within 72 hours of exposure in a dose of 1.25 to 5 ml intramuscularly will modify or prevent the disease.The VZ Ig is particularly useful in newborn.A live attenuated vaccine has been launched in Japan.The scroconversion rate of the vaccine is more than 90%.The side effects include mild local reaction or rash.There is a controversy about general use of chicken pox vaccine because:
a)Vaccination prevents the disease in childhood but later on if child is exposed to the virus the disease is more severe as compared to mild early childhood chicken pox.
b)The live attenuated virus may establish itself as latent infection which may produce Zoster or chicken pox like disease at a later age.
c)The natural disease is mild and passes away if complications are prevented and reliable immunity is produced.

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