The varicella-zoster virus.
Both chickenpox and shingles are caused by the varicella-zoster virus (VZV), a type of herpes virus. The virus is spread when you come in contact with the rash or by sneezing, coughing, and breathing -- in other words, when someone with chickenpox sneezes or coughs, there are droplets with the VZV virus in the air. Introduction. The varicella-zoster virus (VZV) can cause 2 diseases: chickenpox (varicella) and shingles (herpes zoster). Before a vaccine was developed in 1994, chickenpox was a common contagious childhood disease that produced itchy blisters, but rarely caused serious problems. Causes of chickenpox. Chickenpox is caused by the varicella-zoster virus. You catch it by coming into contact with someone who is infected. Chickenpox is a very contagious infection. Around 90% of people who have not previously had chickenpox will become infected when they come into contact with the virus.  Chickenpox (varicella) is a contagious illness that causes an itchy rash and red spots or blisters (pox) all over the body. Chickenpox can cause problems for pregnant women, newborns, teens and adults, and people who have immune system problems that make it hard for the body to fight infection. If the virus becomes active again, it can cause a painful viral infection called shingles. Chickenpox is caused by the varicella-zoster virus. It can spread easily. You can get it from an infected person who sneezes, coughs, or shares food or drinks. Top of Page. Herpes zoster, also known as zoster and shingles, is caused by the reactivation of the varicella-zoster virus (VZV), the same virus that causes varicella (chickenpox). Primary infection with VZV causes varicella. Once the illness resolves, the virus remains dormant (latent) in the dorsal root ganglia. People who have not had varicella and never received chickenpox vaccine can get infected with VZV from someone with herpes zoster. If this happens, they are at risk of developing varicella not herpes zoster. The virus spreads when a person has direct contact with the active herpes zoster lesions. Shingles is caused by the same virus that causes chickenpox. Once you have had chickenpox, the varicella-zoster virus lies dormant in your nerves and can re-emerge as shingles. Shingles, which is characterized by a rash of blisters, can be very painful. But it is not life threatening. Introduction. The varicella-zoster virus (VZV) can cause 2 diseases: chickenpox (varicella) and shingles (herpes zoster). Before a vaccine was developed in 1994, chickenpox was a common contagious childhood disease that produced itchy blisters, but rarely caused serious problems. Risk Factors. The varicella-zoster virus is responsible for both chickenpox and herpes zoster, but its method of infection is different in both diseases. 1  Both the active varicella and zoster form of the virus can cause chickenpox. 2  The shingles virus in its latent (inactive) form is never contagious. Developing Shingles. Shingles itself can develop only from a reactivation of the varicella-zoster virus in a person who has previously had chickenpox. In other words, shingles itself is never transmitted from one person to another either in the air or through direct exposure to the blisters. Herpes zoster, also known as zoster and shingles, is caused by the reactivation of the varicella-zoster virus (VZV), the same virus that causes varicella (chickenpox). Primary infection with VZV causes varicella. People who have not had varicella and never received chickenpox vaccine can get infected with VZV from someone with herpes zoster. If this happens, they are at risk of developing varicella not herpes zoster. The virus spreads when a person has direct contact with the active herpes zoster lesions. Diagnosis. Treatment. Causes of chicken pox Chicken pox is directly caused by the varicella-zoster virus, a member of the herpes virus family. Additionally, chicken pox spreads very easily from one person to another. The virus is spread through direct contact with skin lesions, oral secretions or via the air. Risk factors. People at risk of contracting chickenpox include anyone who hasn't been vaccinated or who has never had the disease. People who've been vaccinated against chickenpox are usually immune to the virus. The same is true of anyone who has had chickenpox in the past.
http://umm.edu/health/medical/altmed/condition/varicellazoster-virus http://www.nhs.uk/Conditions/Chickenpox/Pages/Causes.aspx http://www.webmd.com/vaccines/tc/chickenpox-varicella-topic-overview http://www.cdc.gov/shingles/hcp/clinical-overview.html http://umm.edu/health/medical/altmed/condition/varicellazoster-virus http://www.nytimes.com/health/guides/disease/chickenpox/risk-factors.html http://www.cdc.gov/shingles/hcp/clinical-overview.html http://ehealthforum.com/health/chicken_pox_causes_and__risk_factors-e378.html
factors that affect the cause of chickenpox