[The Scientist (OP)]

Can it be spread and passed on to others in body contact or sharing the same spoon when eating? What do you think? Please share your views. Thanks!

[Bill.D.Katt.]

Yes. That is how it is normally spread. I remember when someone in my first grade got it, then a large portion of the class was out for a while afterwards. I think contact is how most parents used to get their kids to contract the virus. That's how I got mine.

[CliffordK]

There is now a good vaccine for chickenpox.

It is believed that once you contract the disease, it lies dormant in your nervous system for the rest of your life (at least for some people)...  then the original strain can re-activate in later life as shingles in the elderly.  The hypothesis of it lying dormant in the nervous system is the explanation for Shingles usually following a dermatome.

I presume that children can contract the disease from people who have an active case of shingles.

[chris]

This is correct.

Chickenpox - also known as Varicella Zoster Virus (VSV) - is a member of the herpesvirus family. The agent spreads via the respiratory route from particles breathed out by or released from the skin vesicles of an infected individual.

The initial (primary) infection is in lymphoid tissue (usually tonsils and adenoids) triggering a primary viraemia which seeds the lungs. From there infected lymphocytes ferry the virus around the body, infecting other tissues en-route. The most visible manifestation are the skin lesions which are small blisters (3-5 mm across). These are filled with a straw-coloured fluid that is laden with infectious virus. When one of these bursts the particles are released into the environment. They can contaminate surfaces, but chickenpox is an enveloped virus and so its ability to remain viable in this situation for long periods is low. Consequently most secondary cases occur when a susceptible individual breathes in some particles following significant, close exposure to an infectious case.

Following the primary infection the virus gains access to primary sensory nerve endings and thence to the nerve cell bodies in the spinal and trigeminal ganglia where the viral DNA is added, in a circularised semi-quiescent form, alongside the host DNA in the nerve cell nuclei.

Periodically, the viral genome reactivates, triggering the production of viral proteins and / or viral particles which can be shipped back down the nerve to the patch of skin it supplies. In the absence of an effective immune response the overlying skin can develop blisters and the ensuing syndrome is known as shingles. Like primary chickenpox, these blisters are fully infectious and may transmit the virus to a susceptible person.

Usually, however, these reactivation events do not provoke shingles because the immune response is sufficiently robust to contain the virus before it can infect skin cells. In this way, these periodic reactivations serve to re-prime the immune system, helping to maintain high antibody levels. This is known as the Hope-Simpson model, after the man who first suggested it.

Primary chickenpox infection can be prevented or deferred with a live vaccine (based on a weakened or attentuated virus known as the Oka strain), although, despite its popularity in America, the long-term benefits of which remain unknown; that is, there is some concern that immunity may wain in adulthood, rendering recipients vulnerable to primary wild-type chickenpox and thus an enhanced risk of serious consequences such as pneumonitis.

Chris

[The Scientist (OP)]

What will happen to those who scratch their 'chicken pox'?

[Variola]

What will happen to those who scratch their 'chicken pox'?

Well it will help spread the virus, but apart from that you can be left with scars from them, or secondary infections maybe able to infect the pox wound. So advice is to avoid scratching them if as all possible, but that is not easy I know.