Resource Packages: Herpes

Historical Overview

Chickenpox and shingles are caused by the same varicella-zoster virus (VZV). Chickenpox occurs when a person is infected with the virus for the first time. Shingles (herpes zoster) occurs only in people who have had chicken pox in the past and represents a reactivation of the dormant varicella virus.

The name “zoster”’ was coined by the ancient Greeks, who gave this term to the belt a warrior used to secure his armour. The medical profession adapted the term herpes zoster because of the chain-like presentation of shingles.

Human (alpha) herpesvirus 3 (varicella-zoster virus) is a member of the Herpesvirus group.

Recent Developments

The primary infection of varicella-zoster virus results in chickenpox, manifested by a generalized, pruritic, vesicular rash with mild fever and systemic symptoms. Chickenpox is often more severe in immunocompromised patients.

Like all herpesviruses, a characteristic of varicella-zoster is its ability to remain latent within the body. Following a primary infection, the virus enters the peripheral nerves and moves to a central nerve ganglion (a group of nerve cells in bodies lying outside the central nervous system). Latent varicella-zoster virus is located in the dorsal root ganglion near the spine. Later, sometimes decades later, the virus may be reactivated. The trigger can be stress or simply the lower immune competence associated with aging.

Reactivation results in shingles. Lesions may appear in crops in irregular fashion along nerve pathways, distributed about the waist although facial shingles and infections of the upper chest and back also occur. They are usually unilateral and deeper seated and more closely massed than those of chickenpox but histologically they are identical. Severe pain and paresthesia are common and as many as 30% of the elderly may suffer ongoing pain in the affected area. Persons with Human Immunodeficiency Virus (HIV) are also at an increased risk of shingles.

Shingles seldom occurs in people under the age of twenty and by far the highest incidence is in the elderly population.

A person must have already had chickenpox in the past to develop shingles. Contact with an infected individual does not cause another person’s dormant virus to reactivate. However, the virus from a patient with shingles may cause chickenpox in someone who has not had it before.

The varicella-zoster virus is transmitted person-to-person by:

Direct contact with the infected person’s droplets
Airborne spread of vesicle fluid or respiratory tract secretions
Occasionally from the shingles vesicle fluids

Incubation Period

Is usually from 2 to 3 weeks, commonly 13-17 days. It may be prolonged for as long as 28 days by the use of varicella-zoster immune globulin (VZIG)

Standard precautions (see Table 1) - should be practiced at all times.

Transmission-based precautions- are used for patients known to be infected or colonised with epidemiologically important pathogens for which additional precautions beyond Standard Precautions are needed to interrupt transmission in health care facilities.

Patients with shingles require airborne and contact precautions.

Notification to the Public health Unit - chickenpox and shingles are not notifiable diseases to the Public Health Unit

References

Benenson A S ed,1995, Control of Communicable Diseases in Man. An official report of the American Public Health Association. 16th ed, American Public Health Association, Washington.

Bennett J V, Brachman P S, eds 1992, 3rd ed, Hospital Infections. Little, Brown and Company, Boston.

Committee on Infectious Diseases, Red Book Report of the Committee on Infectious Diseases. 24th ed, 1997, American Academy of Pediatrics, America.

Grist N R, Ho-Yen O D, Walker E, Williams G R, 1993, 2nd ed, Diseases Of Infection. Oxford University Press, Oxford.

NSW Health Department, 1999, Infection Control Policy 99/87 AIDS/Infectious Diseases Branch, Sydney.

Tortora A G, Funke B, Case C, Microbiology An Introduction.5th ed,1994,The Benjamin/Cummings Publishing Company Inc, California.

Reid D, Grist N R, Pinkerton I W, Infections in Current Medical Practice. Butterworth, London.

Wenzel R P, Prevention and Control of Nosocomial Infections. 1993, 2nd ed, Williams and Wilkins, Baltimore.

Shingles (herpes zoster) Fact Sheet, New York State Department of Health, Bureau of Communicable Disease Control, April 1996.

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