Page content: Victorian statutory requirement | Infectious agent | Identification | Incubation period | Public health significance & occurrence | Reservoir | Mode of transmission | Period of communicability | Susceptibility & resistance | Control measures | Outbreak measures

Victorian statutory requirement

Notification is not required.

School exclusion: young children with cold sores who are unable to comply with good hygiene practices should be excluded while the lesion is weeping. Lesions should be covered by a dressing where possible.

Infectious agent

Human herpes simplex virus (HSV) types 1 and 2 cause disease.

Identification

Clinical features
Cold sores are the most common manifestation of herpetic infection and are characterised by a localised primary lesion, latency and a tendency to local recurrence.

In children with atopic dermatitis and immunosuppressed patients, herpes simplex virus may disseminate causing a generalised eruption that requires hospitalisation for intravenous antiviral therapy. Herpes simplex may become chronic in patients with HIV infection with recalcitrant crusted lesions and ulceration. Herpes simplex may be complicated by erythema multiforme which is often more disabling than the infection itself. Herpes simplex virus infection may cause severe extensive disease in immunosuppressed individuals.

HSV types 1 and 2 generally produce distinct clinical syndromes depending on the portal of entry.

HSV type 1
The primary infection may be mild and generally occurs in early childhood before the age of five years. About ten per cent of primary infections cause a more severe form of disease manifested by fever and malaise. This may last a week or more and can be associated with vesicular lesions leading to ulcers in and around the mouth (gingivostomatitis), eye infection (keratoconjunctivitis), a generalised vesicular skin eruption complicating chronic eczema or more rarely encephalitis.

Features of gingivostomatitis include ulceration of the tongue, gums, lips and anterior buccal mucosa, severe systemic toxicity and lymphadenopathy.

Reactivation of latent viral infection in the dorsal root ganglia results in cold sores appearing as clear vesicles on an erythematous base. These usually occur on the face and lips and crust and heal in a few days. This reactivation may be precipitated by trauma, fever, environmental conditions such as windy days, sunburn or intercurrent disease.

HSV type 2
This virus is the usual cause of genital herpes although this can also be caused by type 1 virus. Genital herpes occurs mainly in adults and is sexually transmitted. Primary and recurrent infections occur, with or without symptoms.

The principal sites of primary disease in women are the cervix and vulva. Recurrent disease generally involves the vulva, perineal skin, legs and buttocks. In men, lesions appear on the glans penis or prepuce, and in the anus or rectum of those engaging in anal sex. Other genital or perineal sites as well as the mouth may also be involved in either gender depending on sexual practices.

HSV 2 infections are rarely associated with aseptic meningitis and radiculitis.

Method of diagnosis
The diagnosis may be suggested by cytologic changes in tissue scrapings or biopsy. Confirmation is made by direct fluorescent antibody tests, by isolation of the virus from oral or genital lesions or other sites, or by detection of HSV DNA by nucleic acid testing in lesion or spinal fluid. Techniques are also available to differentiate type 1 from type 2 antibody if required.

Incubation period

The incubation period varies from two to twelve days.

Public health significance & occurrence

Asymptomatic infections with HSV type 1 virus are common. Seventy to ninety per cent of adults have circulating antibodies to HSV type 1 virus indicating previous infection.

HSV type 1 is a common cause of meningoencephalitis. Vaginal delivery in pregnant women with active genital infection carries a high risk of disseminated visceral infection, encephalitis and death to the newborn.

HSV type 2 is frequently associated with sexually transmitted infections and 20–30% of adults have antibody evidence of exposure. The prevalence is greater in socio-economically disadvantaged groups and those with multiple sexual partners.

Reservoir

Humans.

Mode of transmission

Contact with HSV type 1 in the saliva of carriers is the most important mode of spread. Contact of health care workers with patients who are shedding HSV may result in an infection of the tip of the finger (herpetic whitlow). It begins with intense itching and pain and is followed by vesicle formation and then ulceration.

Transmission of HSV type 2 to non-immune adults is usually by sexual contact.

Period of communicability

Secretion of virus in the saliva may occur up to seven weeks after recovery from stomatitis.
Patients with primary genital lesions are infective for seven to ten days. Those with recurrent disease are infectious for four to seven days with each episode.

Susceptibility & resistance

Everyone is susceptible to infection. The disease does not usually confer protective immunity because the virus tends to become latent in dorsal root ganglia of the spine where it may become reactivated at a later date.

Control measures

Preventive measures
No vaccine is currently available.

Health education and personal hygiene should be directed toward minimising transfer of infectious material and reducing the risk of exposure to high risk groups.

Emphasise personal hygiene to minimise the transfer of infectious material. Wear gloves when in direct contact with infectious lesions and wash hands with soap and water afterwards.

Use of latex condoms during sexual intercourse decreases the risk of infection.

Control of case
Non-genital herpes
For symptomatic treatment of minor attacks, use povidone iodine 10% paint applied three times daily. Also consider topical antiviral therapy. Therapy should be self-initiated and commenced at the earliest sign of onset. Consult the current version of Therapeutic guidelines: antibiotic (Therapeutic Guidelines Limited).

Sun protection is important in preventing recurrences of facial herpes simplex.

Specialist advice on systemic antiviral treatment should be sought for:

• severe primary or severe recurrent attacks
• attacks complicated by erythema multiforme
• primary or recurrent attacks in HIV-infected patients or the immunosuppressed.

Patients with active lesions should have no contact with newborns, children with burns or eczema and immunosuppressed patients. Consider caesarean section before the membranes rupture when primary or recurrent genital infections occur in late pregnancy to minimise the risk of neonatal infection.

Contact isolation is required for disseminated severe infections and for infected neonates because of the risk to other neonates or pregnant women.

Anogenital herpes
Patients should be fully screened for other STIs, including HIV infection, on their first presentation.

For initial attack or infrequent recurrent attacks treatment usually consists of valaciclovir, famciclovir or aciclovir. For suppression of frequent recurrent attacks aciclovir or valaciclovir are generally used. Consult the current version of Therapeutic guidelines: antibiotic (Therapeutic Guidelines Limited).

If there is breakthrough during prophylaxis, higher doses may be successful. Relapse may occur at the cessation of prophylaxis.

Control of contacts
None applicable.

Control of environment
None applicable.

Outbreak measures

None applicable.