Infectious Mononucleosis (Glandular Fever)

In document Blue Book (Page 105-108)

Victorian Statutory Re q u i re m e n t

Statutory notification not required.

Infectious Agent

Epstein-Barr virus (EBV).

Clinical Features

It is an acute viral infection affecting mainly young adults.

Clinical features include fever, sore throat (usually with exudative pharyngotonsillitis) and lymphadenopathy.

Splenomegaly occurs in 50 per cent of cases; jaundice in 4 per cent.

In young children the disease is mild or asymptomatic.

Duration is from one to several weeks.

The disease is rarely fatal.

A chronic form is suggested as one of the causes of Chronic Fatigue Syndrome.

A syndrome resembling infectious mononucleosis clinically and haematologically may be caused by herpesvirus 6, cytomegalovirus or toxoplasmosis.

Public Health Significance and Oc c u r re n c e

Glandular fever is most commonly seen in high school and university students.

About 50 per cent of those infected will develop the disease that is spread by close, personal contact.

Occurrence is worldwide and widespread in early childhood in developing countries.

Method of Diagnosis

A full blood examination shows mononucleosis and lymphocytes of 50 per cent or more, including 10 per cent or more atypical cells.

Paul Bunnell Test.

Liver Function Tests (AST, ALT) abnormal.

Serological

ELISA IgG and IgM for viral capsid antigen.

ELISA IgG for nuclear antigen, takes two to three months to become positive.

Re s e r voi r

Humans.

Mode of Transmission

It is transmitted by person-to-person spread by the oropharyngeal route via saliva.

Young children may be infected by saliva on the hands of attendants or on toys.

Incubation Period

From four to six weeks.

Period of Communicability

The period of communicability is prolonged.

Pharyngeal excretion may persist for a year or more after infection.

Healthy adults may be long-term oropharyngeal carriers.

Susceptibility and Resistance

Infection confers a high degree of resistance.

Reactivation of EBV may occur in immunosuppressed individuals.

Control of Case

Isolation is not necessary.

Tre a t m e n t

None. Steroids may be of some value in severe, toxic cases.

Control of Contacts

Investigation of contacts is not necessary. No immunisa-tion is available.

Preventive Measures

• Use hygienic measures including hand washing to help prevent spread.

• Disinfect articles soiled with nose and throat dis-charges.

Epidemic Measures

None.

Legionellosis

• There is usually multi-system involvement with diar-rhoea, vomiting, mental confusion, delirium and renal failure.

• In epidemics, it has an attack rate of up to 5 per cent and a case fatality rate of around 15 per cent.

• Legionnaires’ disease was made notifiable in Victoria in 1979.

Pontiac fever:

• The non-pneumonic form, presents mainly as a flu-like illness with spontaneous recovery and no reported deaths.

• It has a high attack rate (95 per cent) and outbreaks have been reported overseas.

• Pontiac fever has not been reported in Australia.

• It was made notifiable in Victoria in May 1990.

Public Health Significance and O c c u r re n c e

Sporadic and epidemic forms of Legionnaires’ disease have occurred overseas and in Australia. Major out-breaks have been reported in South Australia and New South Wales, but not in Victoria.

Most of the overseas outbreaks have been associated with cooling towers and warm water systems.

Some outbreaks have occurred in hospitals where the case fatality rate has been high (for example, in 1985 at Stafford District Hospital in the UK, the case fatality rate was 28 per cent).

The largest outbreak in Australia occurred at

Wollongong, NSW, in 1987 where there were at least 44 cases and 10 deaths. The implicated cooling tower was situated 50 m to 70 m from the Gateway Shopping Centre that was visited by most of the cases.

Victorian Statutory Re q u i re m e n t

Group A notification, Prevention of Legionellosis Health (Infectious Diseases) Regulations 1990, Division 3.

Infectious Agent

The infectious agent is Gram negative bacilli belonging to the genus Legionella.

There are currently more than 30 species, but L.

pneumophila (with 14 recognised serogroups) is respon-sible for at least 75 per cent of cases in Australia and overseas.

Variations in the species/serogroups implicated have been noted in a number of countries at different times. In 1988, L. micdadei accounted for the majority of cases reported in Victoria. In 1993, 20 of the 37 reports of Legionellosis in Victoria were caused by L. longbeachae.

Another species, L. bozemanii, has been implicated in Victorian cases.

Though commonly found in aquatic habitats, Legionella spp. are fastidious organisms requiring specific condi-tions for culture in the laboratory.

The bacteria will not grow on conventional culture media.

Clinical Features

Legionellosis (infection by any Legionella species) is an acute bacterial infection with two recognised presenta-tions:

Legionnaires’ disease:

• This is the pneumonic form of the illness where the patient typically presents with severe pneumonia that frequently culminates in respiratory failure.

• Early symptoms are anorexia, malaise, myalgia and fever (flu-like).

In 1988–1989, an outbreak, where L. longbeachae SG1 was implicated, occurred in South Australia. Epidemio-logical investigations found an association with the use of potting mix. Further work by the Institute of Medical and Veterinary Science, Adelaide (IMVS) found L.

longbeachae to be present in approximately 70 per cent of samples of commercial potting mix tested.

Case fatality in the Victorian cases is around 20 per cent.

Since the disease was made notifiable in 1979, the number of cases has been slowly increasing over the years, possibly due to increased awareness on the part of the clinician.

Case Definition and Method of

In document Blue Book (Page 105-108)

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