General consideration for the control of communicable diseases in Aotearoa New Zealand

Control of communicable diseases continues to be one of the highest public health priorities, both nationally and internationally. Emerging and re-emerging microbial threats and drug resistance pose an ever-increasing challenge to public health practitioners. Added to this are the high public expectations of protection from public health hazards and increasing media interest in public health safety.

The Communicable Disease Control Manual aims to inform and assist those at the frontline of public health action, namely the medical officers of health, health protection officers and staff at public health units. The primary purpose of the manual is to describe the standard practice that public health services should normally follow to prevent and control notifiable diseases.

Information is contained within the disease-specific chapters, including case definitions and the laboratory evidence required for case confirmation. Some important general considerations are outlined below, and in the appendices.

Under the Health Act 1956, attending health practitioners are required to notify their local medical officer of health of any notifiable disease they suspect or diagnose. Notification data are recorded on a computerised database installed in each public health service and are used to guide local control measures. The data are collated and analysed at the national level by the New Zealand Institute for Public Health and Forensic Science Limited (PHF Science): Kenepuru Science Centre on behalf of the Ministry of Health Communicable Diseases Team.

A revised schedule of notifiable diseases came into effect on 1 June 1996. The revision was the most comprehensive change to the schedule since the Health Act was enacted in 1956. Ten years later, the Health Amendment Act 2006 added the statutory obligation for laboratories to notify notifiable diseases to a medical officer of health on suspicion and confirmation. This requirement came into effect in December 2007. To standardise laboratory notification across the country, an agreed set of algorithms for the notifiable diseases was produced in 2007 and were updated in 2021.

Other changes since 1996 include the addition of other notifiable infectious diseases to the schedule including:

• sudden acute respiratory syndrome (SARS)
• highly pathogenic avian influenza (HPAI)
• Cronobacter species invasive disease
• invasive pneumococcal disease
• non-seasonal influenza
• Q fever
• Verotoxin-producing or Shiga toxin-producing Escherichia coli (VTEC/STEC)
• Middle East Respiratory Syndrome (MERS)
• Novel coronavirus capable of causing severe respiratory illness
• COVID-19.
• Invasive group A streptococcal infection

Most recently, the Health (Protection) Amendment Act (2016) has introduced a category of diseases that are notifiable on an anonymised basis, the diseases in this category are AIDS, HIV, gonorrhoeal infection and syphilis. The category can be added to over time by Order in Council. This legislation also allows for improved management of people with infectious diseases and their contacts.

Notifications provide the basis for the surveillance and control[1] (external link) of diseases in New Zealand. Public health control measures are required in response to individual cases of some diseases, such as meningococcal disease and tuberculosis, and in response to outbreaks of other diseases, such as campylobacteriosis and cryptosporidiosis.

As notification by health practitioners is required on reasonable suspicion, the level of public health response while awaiting case confirmation will depend on risk assessment of the case.

The need for effective disease surveillance and control is increasing, as are people’s expectations of being protected from disease threats. Surveillance is seen as a key strategy in preventing infectious diseases. Diseases are specified in the Health Act 1956 as notifiable infectious diseases (Schedule 1, Part 1), other infectious diseases (Part 2 of that Schedule) and non-infectious notifiable diseases (Schedule 2). Tuberculosis, previously notifiable under the Tuberculosis Act 1948, has now been included in Part 1, Section B of Schedule 1 of the Health Act.

Notification confers special status. It provides a legal requirement for reporting, enables cases of disease to be notified without breaching the Privacy Act 2020 and should assist in making a complete identification of cases and their contacts if required. The decision to make a disease notifiable is based on the disease’s public health importance, as measured by such criteria as incidence, impact and preventability.

Attending health practitioners and laboratories notify a disease to the local medical officer of health, allowing the medical officer of health to assess the public health risk, including to:

• identify cases of disease and contacts that require immediate public health measures
• monitor disease incidence, distribution and changes and alert health workers to changes in disease activity in their area
• identify outbreaks and support the effective management of such outbreaks
• assess disease impact and help set priorities for prevention and control activities
• identify risk factors for diseases to support the development of effective prevention measures
• evaluate prevention and control activities
• identify and assess emerging hazards
• generate and evaluate hypotheses about disease occurrence

For legal details on information requirements, refer to the Health (Infectious and Notifiable Diseases) Regulations 2016. (external link)

See the Health Act 1956 (external link) for the most up to date list of notifiable diseases.

Schedule 1 Infectious diseases [i] (external link)

Part 1 Notifiable infectious diseases

Section A—Infectious diseases notifiable to medical officer of health and local authority

• Acute gastroenteritis [ii] (external link)
• Campylobacteriosis
• Cholera
• Cryptosporidiosis
• Giardiasis
• Hepatitis A
• Legionellosis
• Listeriosis
• Meningoencephalitis—primary amoebic
• Salmonellosis
• Shigellosis
• Typhoid and paratyphoid fever
• Yersiniosis

Section B—Infectious diseases notifiable to medical officer of health

• Anthrax
• Arboviral diseases
• Brucellosis
• COVID-19
• Creutzfeldt Jakob Disease and other spongiform encephalopathies
• Cronobacter species
• Diphtheria
• Haemophilus influenzae b
• Hepatitis B
• Hepatitis C
• Hepatitis (viral) not otherwise specified
• Highly Pathogenic Avian Influenza (including HPAI subtype H5N1)
• Hydatid disease
• Invasive group A streptococcal infection
• Invasive pneumococcal disease
• Leprosy
• Leptospirosis
• Malaria
• Measles
• Middle East Respiratory Syndrome
• Monkeypox (mpox)
• Mumps
• Neisseria meningitidis invasive disease
• Non-seasonal influenza (capable of being transmitted between human beings)
• Novel coronavirus capable of causing severe respiratory illness
• Pertussis
• Plague
• Poliomyelitis
• Q fever
• Rabies and other lyssaviruses
• Rheumatic fever
• Rickettsial diseases
• Rubella
• Severe Acute Respiratory Syndrome
• Tetanus
• Tuberculosis
• Verotoxin-producing or Shiga toxin-producing Escherichia coli
• Viral haemorrhagic fevers
• Yellow fever

Section C—Infectious diseases notifiable to medical officer of health without identifying information of patient or deceased person

• Acquired Immunodeficiency Syndrome (AIDS)
• Gonorrhoeal infection
• Human Immunodeficiency Virus (HIV) infection
• Syphilis

Part 2 Other infectious diseases

• Chancroid
• Chlamydia
• Herpes simplex
• Impetigo contagiosa
• Influenza
• Non-specific urethritis
• Pediculosis
• Scabies
• Soft chancre
• Streptococcal infection group A
• Varicella-zoster infection
• Venereal granuloma (Lymphogranuloma venereum or granuloma inguinale)
• Venereal warts

Part 3 Quarantinable infectious diseases

• Avian influenza (capable of being transmitted between human beings)
• Cholera
• Middle East Respiratory Syndrome
• Non-seasonal influenza (capable of being transmitted between human beings)
• Novel coronavirus capable of causing severe respiratory illness
• Plague
• Viral haemorrhagic fevers (capable of being transmitted between human beings)
• Yellow fever

Schedule 2 Diseases notifiable to medical officer of health (other than notifiable infectious diseases)

Section B—Other conditions

• Cysticercosis
• Decompression sickness
• Lead absorption equal to or in excess of 0.24 µmol/l
• Poisoning arising from chemical contamination of environment
• Taeniasis
• Trichinosis

This guidance explains measures concerning the notification and management of infectious diseases which were incorporated into the Health Act 1956 and commenced on 4 January 2017.

Targeted primarily at notifying health practitioners and laboratories, and infectious disease managing public health practitioners, the guidance explains how the new legislation should be applied.

See the full guidance document (external link).

This page summarises information from the full Guidance on Infectious Disease Management under the Health Act 1956 (external link) with sections on notification, contact tracing and public health measures.

See the full Summary document (external link).

The International Health Regulations (IHR) 2005 (external link), which entered into force in June 2007, takes an all-risks approach to the management of global threats to public health. While all potentially serious hazards are covered, in practice the day-to-day focus remains on communicable diseases.

Under the IHR 2005, New Zealand must fulfil the following obligations.

1. New Zealand must develop and maintain the capacities to detect, investigate, manage and report all potentially serious disease-related events. These capacities must be in place locally/regionally, nationally and at the border, such as international airports.
2. New Zealand must establish an IHR National Focal Point (NFP) to provide a single point of contact between this country and the World Health Organization (WHO). This NFP performs a whole-of-health-sector, whole-of-government role in collating and disseminating relevant information. The Office of the Director of Public Health in the Ministry of Health performs this NFP role.
3. The Ministry of Health must receive and rapidly assess the significance of any reports of potentially serious public health events to determine whether or not the NFP should report the event urgently to WHO (see below). Such assessments include using the ‘Decision Instrument’ as provided for in Annex 2 of the IHR 2005.
4. Within 72 hours of the Ministry receiving relevant information, the NFP must notify WHO of events involving any case of smallpox, poliomyelitis, SARS or human influenza caused by a new subtype.
5. Within 48 hours of the Ministry of Health receiving information of any event involving cholera, pneumonic plague, yellow fever, viral haemorrhagic fevers, West Nile fever or any unusual or potentially serious public health event, the NFP must have assessed the event using the Decision Instrument, and where notification is required, notify WHO within a further 24 hours.

Designated officers and public health units play a vital role in ensuring that New Zealand meets the obligations listed above, and in particular they should maintain close communication with the Ministry of Health to ensure that the requirements listed under points 4 and 5 above are able to be discharged in a timely manner.

As well as serious public health events, communications between IHR national focal points and WHO take place on disease cases and contacts that are of relevance to other countries – for example, where someone has been identified as being infectious while staying in another country or aboard a plane. Designated officers and public health units who are alerted to such instances should send this information to the Office of the Director of Public Health as the IHR National Focal Point for New Zealand. If in doubt about what information to notify, contact Office of the Director of Public Health for advice.

[1] In the Health Act 1956, the broader term ‘management’, rather than ‘control’, is used for infectious diseases.

[i] During times of increased incidence, health practitioners may be requested to report, with informed consent, to their local medical officer of health cases of communicable diseases not included on this list.

[ii] Not every case of acute gastroenteritis is necessarily notifiable, only those where there is a suspected common source or from a person in a high-risk category (for example, a food handler, an early childhood service worker) or single cases of chemical, bacterial or toxic food poisoning, such as botulism, toxic shellfish poisoning (any type) and disease caused by Verotoxin- or Shiga toxin-producing Escherichia coli (VTEC/STEC).