from Part VIII - Major Human Diseases Past and Present
Published online by Cambridge University Press: 28 March 2008
Varicella (chickenpox) is an acute infection of short duration caused by Varicella-Zoster virus (VZV), which is spread in the early stages of disease by droplets of secretions from the nasopharynx. It is followed by lifetime latency that may be broken in occasional patients by reactivation of virus in sensory ganglia manifested as herpes zoster (shingles).
Epidemiology and Incidence
Chickenpox is endemic worldwide, is highly communicable, and commonly appears as epidemics among children who are usually attacked between 2 and 8 years of age. (Infants are protected by transplacental maternal antibodies.) Few escape infection until adult life, and these usually live in isolated rural communities. Probably most of those who have seemed to escape the disease had subclinical infections. (The annual Report of Morbidity and Mortality in the United States shows, for 1984, 221,983 cases of varicella reported from 33 states, an incidence of 138 cases per 100,000 population. The age was known in 28 percent; 56 percent of these cases appeared in the 5- to 9-year age group, less than 6 percent were 15 years of age or older.)
The sporadic reactivation of the virus as shingles is unrelated to exposure to exogenous infection and, in general, is uncommon even in populations in which practically all have had chickenpox. Its peak incidence is after age 50. Of those who develop shingles, only 1 percent have two attacks. Patients with impaired cellular immunity are at risk, and herpes zoster is not uncommon in those suffering from malignant disease.
To save this book to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.