Chicken Pox, pneumonia, birth defects, shingles…..these are just some of the problems brought on by infection with the virus called Varicella Zoster. Varicella Zoster is rather large for a virus; though in the scheme of living organisms, all viruses are tiny—they are only fragments of genetic material, such as DNA, surrounded by a protective protein layer. Viruses are parasites--in order to reproduce, they must enter living cells and take over their duplication “machinery”. And depending on which cells they enter, and how significantly the viral invasion interferes with the cell’s normal function, various problems or illnesses in the “host” arise. Varicella viruses are able to invade primate cells; so gorillas and chimpanzees and humans are all able to get chicken pox and related diseases.
Chicken Pox is the most common form of Varicella Zoster infection and has been described in medical literature since the mid 1500’s. Initially, it was felt to be a mild form of small pox, though several centuries later this was disproven. “Pox” was a term used to describe an affliction as a curse, and the intense itching that accompanied this most common varicella infection certainly earned it that label! In fact, the term “Chicken Pox” is felt by some historians to be derived from the term “itching pox”. Others theorize that the sores resembled wounds from a poultry attack, that is, “chicken pecks.”
The chicken pox virus can invade one’s body by only two routes; inhalation of particles expelled by an ill person nearby, or by direct contact with a moist pox lesion. The majority of cases contracted are from inhalation. A person is highly contagious for a period starting several days before the outbreak until all the skin lesions have crusted and dried. When Varicella Zoster enters a body, it “incubates” for 10-20 days, using lymph gland, liver, and spleen cells to replicate. Finally, it invades the cell’s lining the tiny blood vessels (capillaries) of the skin and causes the classic rash, described to medical students world-wide as “dew drops on a rose petal.” Such a poetic name for such misery!
90 percent of initial, or primary, varicella zoster infections occur in children less than 10 years old, and the antibodies produced in response ensure the sufferers will never get the syndrome of Chicken Pox again. This skin infection though, no matter how vexing, does not cause death. Yet, in some cases the virus goes on to invade lung, liver, and brain tissue and causes much more dangerous issues such as pneumonia, hepatitis, and encephalitis. These illnesses can be deadly, and account for the majority of lives lost to primary Varicella Zoster virus infection. Newborn infants as well as adults are much more prone than children to get these lethal disease variants. And if a woman has not had chicken pox (and so does not have chicken pox immunity) and is exposed during early pregnancy, the destructive virus can attack the fetus and cause “congenital varicella syndrome” resulting in serious neurologic and skeletal birth defects.
Until 1995, the only way to reduce the risk of dangerous Chicken Pox complications was to contract the disease while young. Thus this varicella condition was considered an almost welcome rite of childhood; in fact, “Chicken Pox Parties” were commonly held to promote illness (and the subsequent lifelong immunity) in grade-school-aged kids. But there is a considerable down-side to having Chicken Pox in your past, for it turns out that once the Varicella Zoster enters your body, it almost never leaves! Though the acute illness may be past, viral particles are capable of persisting (in an inactive state) within specific areas of the spine. They “hide out” in sensory nerves cells, that is, the nerves that transmit sensations to the brain, as opposed to the nerves that transmit messages from the brain to the muscles, etc. Usually, the immune system is able to inhibit any activation of viral particles, so the Chicken Pox virus is in a state of hibernation, or, more accurately, incarceration. But sometimes the virus is allowed to duplicate itself and travel along the nerve root pathway of its host cell, and the resulting pain and blistering skin rash is the infamously Shingles. It is theorized that slight imperfections in immune system function, brought on perhaps by physical or psychological stress, are enough to allow Shingles to develop. And if a person is unlucky enough to have a major immune system problem, brought on by chemotherapy or HIV aids for example, the Shingles process can spread throughout the body. In these rare, unfortunate cases, Shingles can be fatal.
The intense discomfort of Shingles, caused by viral infection of the sensory nerves, is noted to be one of the most painful afflictions humans experience. And since the profound distress usually precedes the classic skin rash by several days, the suffering can be compounded by fruitless and potentially risky attempts to find and treat the torment’s source. People with Shingles involving the nerve wrapping around the left side of their chest, for instance, may undergo invasive tests of their heart and lungs. Folks who have involvement of the nerve related with sensations of the jaw have undergone unnecessary root canals. If the nerve involving the right abdomen is affected, needless gallbladder surgery may be performed. Ultimately, though, if one can endure the pain and avoid unnecessary medical procedures, the only permanent effect in a person with normal immunity is scarring of the involved skin. There are two scenarios, however, when there are long-lasting negative effects of Shingles. One is if the nerve attacked is that which innervates the eye. In this case, scarring of the cornea may result in permanent vision loss. The other unfortunate sequel of Shingles is persistent nerve pain in the affected area. Though unusual, this is a stubborn issue that can plague the sufferer for years. Medications can help, but are not curative.
So Varicella Zoster can cause many ailments—Chicken Pox, pneumonia, encephalitis, hepatitis, birth defects, and Shingles. What is the best strategy to defeat this scourge? There are antiviral medications, such as Acyclovir and Famvir, that can reduce illness intensity, but they do not totally vanquish the infecting viral organism. Having Chicken Pox as a child makes one immune to the Chicken Pox Syndrome as an adult, but renders one prone to Shingles. Neither of these plans fully protects someone from the damaging effect of the viral invader. Fortunately, there is now a varicella vaccine that is readily available. The version for children is called a “Chicken Pox Shot.” It is highly effective in preventing infections and is mandated by most public school systems. Note that there is a double benefit, for if someone never gets Chicken Pox, they cannot ever get Shingles! The version made for adults over age 50, presumed to have had or been exposed to Chicken Pox and thus harbor small amounts of the virus in their spines, is called a “Shingles Shot,” and while not markedly effective, it is felt to boost a person’s immune system enough to decrease the likelihood of viral re-activation. The only true cure for Shingles, though, is to deter the Varicella Zoster virus from entering the body in the first place! Prevention is, indeed, the best medicine.
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