21: Viruses of relevance to dentistry

Chapter 21 Viruses of relevance to dentistry

This chapter gives an outline of the viruses that are of special relevance to dentistry. The DNA viruses are described first, followed by the RNA viruses (see Table 4.1).

DNA viruses

Papovaviruses

These DNA viruses infect both humans and animals; however, human disease is infrequent.

Herpesviruses

There are a range of different human herpesviruses, currently numbered 1–8 (see Table 4.3). All of them are structurally similar (enveloped, icosahedral with double-stranded DNA) and infect both humans and animals. They are the most common causes of human viral infections. All have the important property of remaining latent, with the ability to reinfect the host a variable period after the primary infection. Important human pathogens include herpes simplex virus types 1 and 2 (HSV-1 and HSV-2), varicella-zoster virus (VZV), cytomegalovirus (CMV) and Epstein–Barr virus (EBV) (see Chapter 4). Students of dentistry should be thoroughly conversant with the herpes group of viruses as the majority of them either cause oral infection or are intimately associated with orofacial tissues and saliva.

HSV (human herpesviruses 1 and 2)

There are two types of HSV: HSV-1 and HSV-2. They can be differentiated by serotyping, by DNA homology and, to some extent, by clinical disease pattern.

Clinical disease

Disease due to HSV can be either a primary infection, due to first encounter with the virus, or a reactivation or recurrent infection, due to activation of the latent virus.

Varicella-zoster virus (human herpesvirus 3)

This organism causes both varicella (chickenpox) and herpes zoster (shingles) – two different diseases due to an identical organism. Chickenpox is the primary infection, and herpes zoster is the reactivation of illness.

Clinical disease

EBV (human herpesvirus 4)

EBV is widespread in humans, and most adults have antibody to the virus. The virus persists in latent form within lymphocytes after primary infection (lymphotrophic, unlike HSV and varicella-zoster virus, which are neurotrophic). The genome resides in a latent form in B cells; latent EBV infection is common in the population. It is the aetiological agent of a number of diseases:

Jan 4, 2015 | Posted by in General Dentistry | Comments Off on 21: Viruses of relevance to dentistry
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