The first function of the Department, namely, the prevention of disease, and the promotion and conservation of health, derives its authority from the following legislation: the Health Act 1956, the Tuberculosis Act 1948, the Food and Drugs Act 1947, and various regulations under all three Acts. To enable these functions to be carried out, the country has been divided into a number of health districts, each in the charge of a Medical Officer of Health, a medical practitioner with special qualifications, and he is assisted by nurses, inspectors of health, and other professional, technical, and clerical officers. The Health Act is concerned with the control of infectious diseases; the operation of an adequate quarantine service to guard against the introduction of disease by ship or aircraft; the maintenance of a sanitary environment with safe water supplies, sewerage systems, and adequate provision for the removal and disposal of refuse; the control of healthy conditions in homes and other buildings, including places of work; the maintenance of proper hygiene in the preparation, storage, and sale of food; the control of nuisances and offensive trades, of the pollution of rivers and streams, and of the air; and the maintenance of child health.

Control of Infectious Disease

A large number of infectious diseases are required by law to be notified by medical practitioners to the local authority and to the Medical Officer of Health. Every case so notified is promptly visited by a health inspector who gives instructions about the quarantine measures necessary for contacts who attend school or are food handlers. He also sends a report to the Medical Officer of Health who decides what further action, if any, is necessary. By these means possible epidemics are prevented or cut short. These control measures to limit the spread of infectious disease are supplemented by more positive preventive measures such as vaccination and inoculation for the prevention of tuberculosis, typhoid fever, diphtheria, whooping cough, tetanus, and poliomyelitis. Some of this is done by private practitioners with vaccine supplied free of charge, while much of it is done by medical officers and nurses of the Department.

A committee of the Board of Health – the Epidemiology Advisory Committee – assists the Department in consultation on matters concerning the control of infectious diseases.

Tuberculosis Control

Measures for the discovery and treatment of early cases of tuberculosis have been greatly intensified since 1954, with a resultant great reduction in the incidence of tuberculosis and the number of deaths caused by it. This has made it possible to close several sanatoria that were full a few years ago, with other persons awaiting admission.

The chief methods of detection are Mantoux testing, and mass X-ray examination of selected groups. During 1964 chest X-ray examinations were made of 351,743 persons, and 93,608 were Mantoux tested. BCG vaccination was given to 33,034 persons, mostly children between 10 and 14 years of age.

Child Health

The purpose of the School Medical Service is the early detection of abnormality or ill health in pre-school and school children. This work is carried out by school medical officers and public health nurses, and they aim to see each pre-school child at the age of two, and again during the fourth year. Arrangements are made with private doctors for necessary treatment, and advice is given to mothers for the benefit of their children's health.

Children attending the primary schools are examined by a school doctor in their first school year unless they have already been seen during the preceding two years. Other children are examined by nurses twice during their primary-school life, and referred to a medical officer if any defect is found. Every effort is made to persuade mothers to be present at these examinations. Audiometric surveys are made also to detect deafness.

Child Health Clinics

Six Child Health Clinics have been established throughout the country for the investigation and treatment of emotionally disturbed and psychologically maladjusted children. Each clinic is staffed by a specialist paediatrician, a psychiatrist, an educational psychologist, a play therapist, a social worker, and a secretary. There is close liaison between the clinics and the schools, and the social worker investigates the children's home conditions.

Occupational Health

Oversight of the occupational health risks in factories and elsewhere is a responsibility of the Medical Officer of Health working in cooperation with the factory inspectors of the Department of Labour. To assist in this work an Occupational Health Unit, staffed by specialists, is to be established in the National Health Institute. Medical practitioners are required to notify cases of industrial disease seen by them, and this indicates where health hazards exist and preventive action is needed.

Control of Food Standards

The administration of the law governing the quality of food and drugs is exercised by each Medical Officer of Health whose officers take numerous samples for analysis which is carried out by the Dominion Laboratory and its branch laboratories. In addition to maintaining the quality of food, the Food and Drug Regulations specify how food in packets should be labelled so that the purchaser is fully informed as to what he is buying.

Dental Health

Preventive dental treatment for pre-school and school children is an important public health undertaking, and is described more fully in the section dealing with dentistry.

Health Education

Preventive medicine has advanced far beyond the stage when the provision of a healthy environment is the sole aim of the public health authority. Much ill health is caused by errors and indiscretions on the part of the individual, and to correct this, and to teach people to feed themselves aright and to live an active, temperate, and well-balanced life, are important functions of the Department. Newspaper advertisements, booklets and leaflets, posters, films, health talks, and radio broadcasts all play their part in the campaign. Much health education is given in personal day-to-day contact, with individuals and small groups, by dental nurses, public health nurses, inspectors of health, and other field officers.

Medical Statistics

The maintenance of a Medical Statistics Branch is a most important feature of public health administration. The collection and examination of statistical data relating to the causes of morbidity and mortality form an essential foundation on which to build an effective public health policy.

Services for Maori Health

The Maori people, though enjoying equal political rights with their fellow citizens, present certain problems which have their origin in heredity, the lingering effects of old tribal habits and customs, and a sense of values which differs from that of Europeans, and all these pose a problem in the field of public health. The innate vigour of the Maori race is shown by their high birthrate of 46 per thousand population, compared with the European rate of about 25, and a correspondingly more rapid population increase; but the morbidity and mortality statistics of the Maori show higher death rates at all ages, and a greater susceptibility to many types of disease as compared with those of the Europeans.

In attempting to correct this disparity, the Department provides a District Health Nursing Service in all districts where Maoris are numerous, and special attention is given to maternal and child welfare and control of acute infectious diseases and of tuberculosis. These services are additional to the ordinary public health, medical, dental, and hospital services which the Maori shares equally with the European. Much of the increased incidence of ill health in Maoris arises from poor housing, overcrowding, and lack of suitable employment, which are perhaps an unavoidable accompaniment of an extremely high birthrate. The problem is clearly much more than a public health problem, and is closely bound up with education, incentive, occupational training, and suitable employment.

Quarantine Services

Legal provision for the necessary quarantine measures affecting ships and aircraft from overseas is contained in the Health Act and Quarantine Regulations, and this legislation has been drafted to comply with the International Sanitary Regulations adopted in 1951 by the Fourth World Health Assembly. Responsibility for administering the quarantine provisions rests with the Medical Officer of Health of the district, and a port health officer is appointed for each port to act as his deputy. For each international airport a medical practitioner is appointed to act in a similar capacity.

The only diseases for which special quarantine precautions may be taken are set out in the International Sanitary Regulations, and are smallpox, plague, yellow fever, cholera, typhus, and relapsing fever. These are legally known as the “quarantinable diseases”, the only one presenting any danger to New Zealand being smallpox. If any infectious disease other than a quarantinable disease appears on a ship or aircraft, it is dealt with in the same manner as would apply if a case of such disease arose within the country. If a case of a quarantinable disease is present on a ship or aircraft, the procedure to be carried out is set out in the appropriate regulation, the same procedure being followed in all countries.

Since about 1935 the quarantine stations, which were formerly maintained ready for use, have been done away with, it being possible to control the spread of quarantinable diseases by other means, namely, by hospitalisation, vaccination, and isolation or surveillance of contacts.

Control of Air Pollution

The Health Act 1956 provided the Department with additional powers for preventing pollution of the atmosphere. This is not a serious problem in New Zealand, but with the development of the country's industries it could become so unless preventive action were taken in time. Chemical inspectors have been appointed whose main function is to advise industry how to operate with the minimum pollution of the atmosphere, and they are armed with adequate powers to be used when necessary to reinforce their advice.