Varicella Zoster Virus

A virus responsible for causing various diseases, like the chicken pox, post therpetic neuraglia and shingles, the varicella zoster virus is known by different names. The different names of the virus are 'zoster virus', 'chicken pox virus' and 'human herpes virus type 3'.

Varicella Zoster Virus
The virus is spherical in shape and has a diameter of about 150-200 nm. The genome of varicella zoster virus, is similar to that of the herpes simple viruses (HSV). The DNA of the varicella virus is a linear and double-stranded molecule having a length of 125,000 nt. The body of the virus is formed of capsomeres. These capsomeres are enclosed in a lipid layer and are 162 in number. The manner in which the capsomeres are arranged, is known as the icosahedral formation. The entire structure or formation of 162 capsomeres is known as the nucleocapsid. The virus is susceptible to chemicals such as sodium hypochlorite. The different kinds of therapeutic agents and drugs used to treat the virus are zoster-immune globulin, vidarbine and aciclovir.

Varicella Infection
Once the virus infects a person, it goes dormant and stays in his body. After causing the chicken pox disease, the virus becomes dormant and remains in the patient's body. The person affected by chicken pox may develop further complications like pneumonia and encephalitis. The virus travels from the nervous system, where it stays during dormancy to the skin. Here, it causes problems such as dermatomal rash. Other than the rash, it can cause diseases of the spinal cord.

In the United States, amongst every 1000 people, 5 are diagnosed with the varicella virus infection. The risk of varicella infection reduces with age.

Varicella Vaccine
The vaccine that is used in the United States against the varicella virus is Varivax. Developed by the Merck & Co. Inc., the vaccine was isolated in 1970s by a team lead by Mr. Michiaki Takahashi. The Food and Drug Administration of the United States approved the vaccine in the year 1995. This vaccine is used in United States, Australia and other countries thereafter. The efficacy of the vaccine was questioned by doubting its longevity. However, the results of the vaccine indicate the fact to be otherwise. The vaccine has proved to be effective in the treatment of the virus. According to the data recorded in United States, 90% reduction in varicella related diseases has been achieved. The longevity of the vaccine is not in question any more, as it is effective for minimum 10 years.

The drug named Zostavax was approved in the year 2006, for the treatment of this virus. The new drug is more concentrated in its formulation. The immune system becomes weak with age. The vaccine helps in eliciting the immune response in case of adults. Thus, the drug is effective in the treatment of the virus in the infections of adults.

An important and equally dangerous virus, the varicella zoster virus remains a cause of concern.