Control Guideline for Public Health Units

Public health priority: Routine.

PHU response time: If requested by CDB, begin investigating cases within 1 working day of request.

Case management: By treating doctor. PHUs do not follow up cases routinely. Follow up may be required when an unusual mode of transmission is suspected, or through appropriate AHS staff where partner notification is required.

​Contact management: By the treating doctor. AHS specialist staff must assist if requested by the treating doctor or CDB.​

Last updated: 06 September 2004
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  1. Reason for surveillance
  2. Case definition
  3. Notification criteria and procedure
  4. The disease
  5. Managing single HIV notifications
  6. Managing special situations

1. Reason for surveillance

To monitor the epidemiology of human immunodeficiency virus (HIV) infections in NSW and so inform the development of better prevention strategies.

2. Case definition

HIV - Newly Acquired

Newly acquired HIV disease may be diagnosed in individuals aged 18 months or older at the time of blood sample collection. A diagnosis of newly acquired HIV infection excludes a diagnosis of HIV infection (unspecified).

Probable case

A probable case requires laboratory suggestive and clinical evidence.

Laboratory suggestive evidence
  • Detection of HIV by at least one of the following virologic assays (nucleic acid testing for proviral DNA; HIV p24 antigen, with neutralisation; virus isolation), or
  • Repeatedly reactive result on a screening test for HIV antibody followed by a positive result on a western blot.
Clinical evidence

HIV seroconversion illness within the 12 months prior to blood sample collection.

Confirmed case

A confirmed case requires definitive laboratory evidence only.

Definitive laboratory evidence
  • Repeatedly reactive result on a screening test for HIV antibody followed by a positive result on a western blot and laboratory evidence of a negative or indeterminate HIV antibody result in the 12 months prior to blood sample collection, or
  • A group IV indeterminate western blot and detection of HIV by at least one of the following virologic assays (nucleic acid testing for proviral DNA; HIV p24 antigen, with neutralisation; virus isolation). A group IV indeterminate western blot is defined by the presence of a glycoprotein band (gp41, gp120 or gp160) and one or two other HIV specific bands.

HIV - unspecified

HIV infection (unspecified) is diagnosed in individuals aged 18 months or older at the time of blood sample collection, who do not have evidence of HIV acquisition in the previous 12 months. A diagnosis of HIV infection (unspecified) excludes a diagnosis of newly acquired HIV infection.

Probable case

A probable case requires laboratory suggestive evidence only.

Laboratory suggestive evidence

Detection of HIV by at least one of the following virologic assays (nucleic acid testing for proviral DNA; HIV p24 antigen, with neutralisation; virus isolation) in one blood sample only.

Confirmed case

A confirmed case requires definitive laboratory evidence.

Definitive laboratory evidence
  • Repeatedly reactive result on a screening test for HIV antibody followed by a positive result on a western blot. A positive result on a western blot is defined by the presence of a glycoprotein band (gp41, gp120 or gp160) and at least three other HIV specific bands
  • Detection of HIV by at least two virologic assays (nucleic acid testing for proviral DNA; HIV p24 antigen, with neutralisation; virus isolation) performed on at least two separate blood samples.

HIV - child aged less than 18 months at the time of blood sample collection

Probable case

A probable case requires laboratory suggestive evidence only.

Laboratory suggestive evidence

Detection of HIV by one of the following virologic assays (nucleic acid testing for proviral DNA; HIV p24 antigen, with neutralisation; virus isolation) in one blood sample (excluding cord blood) and no subsequent negative HIV virologic or antibody tests.

Confirmed case

A confirmed case requires definitive laboratory evidence

Definitive laboratory evidence

Detection of HIV by at least two virologic assays (nucleic acid testing for proviral DNA; HIV p24 antigen, with neutralisation; virus isolation) on at least two separate blood samples (excluding cord blood).

Acquired immunodeficiency syndrome (AIDS)

A confirmed case requires laboratory evidence and clinical evidence.

Laboratory Evidence

Definitive diagnosis of HIV-1 infection.

Clinical evidence

A diagnosis of at least one of the following clinical conditions:

  • Candidiasis of the bronchi, trachea or lungs - definitive diagnosis only
  • Oesophageal candidiasis - definitive or presumptive diagnosis
  • Invasive cervical cancer - definitive diagnosis
  • Coccidioidomycosis, disseminated or extrapulmonary - definitive diagnosis only
  • Cryptococcosis, extrapulmonary - definitive diagnosis only
  • Cryptosporidiosis of more than one month's duration - definitive diagnosis only
  • Cytomegalovirus retinitis, with loss of vision - definitive or presumptive diagnosis
  • Encephalopathy, HIV related - definitive diagnosis only
  • Herpes simplex: chronic ulcer(s) of more than one month's duration, bronchitis, pneumonitis or oesophagitis - definitive diagnosis only
  • Histoplasmosis, disseminated or extrapulmonary - definitive diagnosis only
  • Isosporiasis, chronic intestinal, or more than one month's duration - definitive diagnosis only
  • Kaposi's sarcoma - definitive or presumptive diagnosis
  • Lymphoma, Burkitt's - definitive diagnosis only
  • Lymphoma, immunoblastic - definitive diagnosis only
  • lymphoma, primary, of brain - definitive diagnosis only
  • Mycobacterium tuberculosis complex, any site, pulmonary or extrapulmonary - definitive or presumptive diagnosis
  • Non-tuberculous mycobacterial disease, disseminated or extrapulmonary - definitive or presumptive diagnosis
  • Pneumocystis carinii pneumonia - definitive or presumptive diagnosis
  • Pneumonia, recurrent bacterial - definitive or presumptive
  • Progressive multifocal leukoencephalopathy - definitive diagnosis only
  • Salmonella septicaemia, recurrent - definitive diagnosis only
  • Toxoplamosis - definitive or presumptive diagnosis
  • Wasting syndrome due to HIV infection - definitive diagnosis only
  • Bacterial infection affecting a child less than13 year of age - definitive diagnosis only
  • Lymphoid interstitial pneumonia and/or pulmonary lymphoid hyperplasia affecting a child less than 13 years of age - definitive or presumptive diagnosis.

(Illnesses indicative of AIDS are defined in ANCA Bulletin 18: Definition of HIV infection and AIDS defining illnesses.)

Epidemiological evidence

Not applicable.

3. Notification criteria and procedure

HIV is to be notified directly to the Communicable Diseases Branch by HIV reference laboratories within one week of diagnosis of a new case. HIV reference laboratories are required to send a notification form with the HIV positive result to the treating doctor seeking information about the case, with instructions to return the form to CBD within 14 days. A copy of the form is simultaneously sent to CDB for entry onto the HIV/AIDS Database.

If CBD does not receive a completed notification form from the treating doctor within 28 days of receipt of the lab notification, CDB sends a follow up request to the treating doctor. If, within 14 days, there is no response to the follow up request a final reminder is sent. The case is then finalised until further information is obtained.

Perinatal HIV

Follow up of a perinatal case is conducted through the NCHECR. The Australian Paediatric Surveillance Unit notify NCHECR of the perinatal case. If the treating doctor indicates that the HIV infected woman has children, copies of the Perinatal Exposure form are forwarded for completion by NCHECR.

AIDS

AIDS is to be notified to PHU by medical practitioners and hospital CEOs on provisional clinical diagnosis. On completion of the AIDS notification form, the form is forwarded to the Public Health Unit, where it is entered onto the Notifiable Diseases Database (NDD). The PHU also forwards a copy to CDB for entry onto the HIV/AIDS Database.

All Public Health Units complete annual active surveillance for unreported cases of AIDS and deaths in a HIV infected person.

4. The disease

Infectious agent

The human immunodeficiency virus (HIV) 1 or 2.

Mode of transmission

HIV is usually transmitted by contact with blood, semen, vaginal secretions or breast milk of an infected person. The virus must be introduced through broken skin, via the placenta or come in contact with mucous membranes for infection to occur. HIV may also be present in the cerebrospinal fluid, saliva, tears, pre-ejaculatory fluid, amniotic fluid, urine and bronchoalveolar fluid of infected persons. However transmission via exposure to these fluids has not been documented.

Routine social or community contact with an HIV infected person carries no risk of transmission. Only sexual exposure and exposure to blood, body fluids or tissues carry a risk.

Documented modes of transmission include:

  • Sharing HIV-contaminated needles
  • Sexual contact (heterosexual or homosexual)
  • Perinatal transmission from an infected mother to a foetus or newborn
  • Breastfeeding
  • Transfusion of infected blood or blood products
  • Needle stick injuries, although the rate of seroconversion is less than that for hepatitis B.

Timeline

The window period (which is the period between exposure and possible laboratory diagnosis) is variable, but the time from infection to the development of detectable antibodies is generally 30 to 90 days. The time from HIV infection to diagnosis of AIDS may be less than a year or longer than 10 years where no treatment is instituted.

The period of infectivity begins early after onset of HIV infection and extend throughout life. Infectiousness is high following initial infection, and is likely to increase as the immune system deteriorates, as characteristic clinical symptoms appear and in the presence of other sexually transmissible diseases.

Clinical manifestations

HIV infection is biphasic. The initial phase, which may be so mild as to go unnoticed, occurs shortly after infection. This acute syndrome resolves spontaneously, and most cases remain asymptomatic for a period of some years. Eventually, however, a progressive immunodysfunction develops, associated with depletion of T4 (CD4+) lymphocytes, which predisposes these individuals to a number of opportunistic infections, tumours and other conditions.

Shortly after exposure, many persons experience a nonspecific illness that may resemble mononucleosis and usually resolves over 2 to 3 weeks. There is typically an abrupt onset, with the following non-specific symptoms (in descending order of frequency):

  • Fever/sweats
  • Myalgia/arthralgia
  • Malaise/lethargy
  • Lymphadenopathy
  • Sore throat
  • Anorexia/nausea/vomiting
  • Headaches/photophobia
  • Rash
  • Diarrhoea.

Most persons remain asymptomatic for years after initial infection; infection can only be determined by antibody or other laboratory testing. Subsequent HIV-related illness may present in a variety of ways such as:

  • Persistent generalised lymphadenopathy
  • Chronic constitutional symptoms such as weight loss, fever or night sweats
  • Neurological disorders, such as dementia, myelopathy or peripheral neuritis
  • Opportunistic infections such as Pneumocystis carinii pneumonia PCP, tuberculosis or chronic candidiasis
  • Malignancies such as Kaposi's sarcoma or lymphomas.

5. Managing single HIV notifications

Response times

Investigation

PHU are not required to routinely follow up HIV or AIDS cases. PHUs may be required to investigate cases in special circumstances (see below).

Data entry

  • CDB maintains a specific HIV/AIDS database entered centrally
  • PHUs must not enter HIV cases onto NDD. Confirmed and probable cases are entered by CDB
  • Confirmed AIDS cases should be entered onto NDD within 5 days of receipt.

Response procedure

The response to a notification will normally be carried by the case's health carers. Sexual Health Service (SHS) staff should assist if requested.

Case management

Investigation and treatment

PHU are not required to routinely follow up HIV or AIDS cases. PHUs may be required to investigate cases if:

  • The patient or doctor requests further investigation
  • CDB requests further investigation because of an unusual clustering or source of infection is suspected.

Education

Clinicians are required to provide pre and post test counselling to patients seeking HIV tests. A range of educational services are available to people diagnosed with HIV through the AIDS Council of NSW and other agencies.

Exposure investigation

  • Where required, PHUs should investigate the source of infection by interviewing the patient using the standard Risk Ascertainment questionnaire
  • Where an unusual clustering or source of infection is suspected the investigations will usually require a specific design and a tailored questionnaire. Ask CDB for assistance.

Isolation and restriction

People with HIV infection must avoid exposing others to their body fluids and (under the Public Health Act) must not knowingly place others at risk of infection.

Health care workers who are HIV infected must not perform exposure-prone procedures.

Environmental evaluation

Usually none. Where nosocomial transmission is suspected, then a review of the facility's infection control procedures will usually be required.

Contact management

Identification of contacts

Contacts are people who have been exposed to the case's blood, semen, vaginal secretions, or breast milk. Follow up of contacts to determine their risk of infection is the responsibility of the case's treating doctor. The doctor may seek the assistance of the Area Health Service staff for this, in which case trained AHS must assist in contact tracing.

Treatment

Contact investigation and treatment should be managed through a medical practitioner or AHS Sexual Health Service Specialists. Contacts should be assessed for risks for HIV, and whether post exposure prophylaxis is warranted.

Education

The treating clinicians must provide counselling and education for contacts.

6. Managing special situations

Cases among health care workers

HIV-infected health care workers must not perform exposure prone procedures. The risk of transmission of HIV to patients of an infected HCW performing exposure-prone procedures must be assessed in accordance with NSW Health Department Circular 99/88. Health care workers should be aware of the need to comply with standard infection control precautions (Circular 2002/45).

Suspected iatrogenic infection

Where iatrogenic infection is suspected, notify CDB immediately.

Cases among recent blood donors

Where a case has donated blood or plasma while infectious, the blood bank and the CDB should be notified immediately.

Suspected transfusion-acquired case

If transfused blood or blood products are suspected as the possible source of infection, the blood bank and the CDB should be notified immediately.

Page Updated: Monday 6 September 2004