This article is a summary of an address given by Dr. C.E. Cook, Senior Medical Officer, Commonwealth Department of Health, to a Conference on Native Employment in the Northern Territory, held in Sydney on the 24th February, 1955.
In the Northern Territory, as in other tropical regions, the environment is ideal for the intense endemicity of certain debilitating diseases of a character and severity likely to seriously deplete or even destroy the labour force. The efficiency of a labour force, apart from any consideration of technical skills, is ultimately determined by the physical ability of an individual to perform his allotted task and his voluntary acceptance of the task, with satisfaction in its performance. Economic interest, therefore, demands that most of these debilitating diseases, which are preventable, should be prevented.
The conditions with which we are immediately concerned and which have hitherto been effectually held in check by sociological environmental factors now no longer operative, may be considered as:
- diseases due to invasion by parasites – communicable diseases;
- pathological conditions developing in response to adverse conditions – insufficient or unsuitable food, exposure to noxious external agencies, etc.
Communicable Diseases
For the present, these are the most numerous, the best understood and therefore the most important when considering practical measures of prevention.
Invasion of the human body by a parasite, if it does not cause death, develops:
- in the infected man, a high level of resistance, which may dislodge the parasite or enable the host to harbour it and still survive with or without some impairment of health;
- in the parasite, an adaptation permitting its survival in the host, withstanding these efforts to dislodge or destroy it.
In a proportion of cases, these two simultaneous developments produce the carrier – a human host apparently in good health and unaffected by the parasitism yet harbouring living parasites and serving as an agency for the infection of new hosts.
Communicable diseases, as we know them, may be regarded as forms of parasitism to which our race, through many generations of exposure, has built up a resistance sufficient to avert fatality. During this period, a process of undersigned culling has removed from amongst us many of those whose inherited constitution has proved incapable of responding to infection by the attainment of a level of resistance sufficient to ensure survival.
Whilst survivors have been acquiring this high grade immunity, we have bred largely from the more responsive stock. In this way we have, over the years, developed a high “herd” immunity. To counter this, the parasites themselves have acquired a greater capacity for invasion and a survival in a hostile environment.
The longer a disease has been endemic in a community, the greater the probability that any individual of that community will survive infection by the prevalent strain of parasite.
Severe outbreaks of communicable disease, with a relatively high mortality, are apt to occur in a community following:
- introduction of a new parasite to which no resistance has been developed;
- lowering of resistance to a familiar parasite – by famine, or other reducing factor, or by a long period of freedom from contact;
- exaltation of invasive power in a familiar parasite – such as may develop after its rapid passage through a large number of susceptible hosts; and
- changes in the environment, which multiply opportunities for the dissemination of the parasite, or expose the community to doses of infective organisms much greater than those to which they have been accustomed.
In short, the prevalence of these diseases and their severity will be determined by the proportion of susceptible persons in the community. Speaking generally, in a European community these susceptibles will be found most frequently amongst children who have not yet been exposed to infection, and have not therefore attained resistance.
Any particular specifies of parasite tends to gain entry to the human body by only one of a number of routes, e.g. through the respiratory tract (air-borne infection), through the alimentary tract (food or water-borne infection), through the skin (direct contact), or by insect inoculation. In the body, the parasite tends to lodge in a particular organ or type of tissue, and its mode of escape, for the purpose of infecting new hosts, will be determined by this site. Respiratory tract infections will normally be disseminated by the escape of large numbers of infective organisms into the air to be breathed by persons in the vicinity; organisms causing alimentary tract infections will escape from the body with the excreta and gain access to new hosts by means of polluted water or food. Parasites dependant upon carriage by blood-sucking insects will circulate in the blood of the skin.
Dissemination of communicable diseases is therefore promoted by conditions found in primitive fixed communities – overcrowding the uncontrolled accumulation of human wastes, and breeding of insect vectors of disease in close proximity to dwellings. Once the parasites have been introduced, the incidence of parasitic disease will be high in communities where sanitation is bad.
In races such as our own, which have lived for many centuries in fixed communities, infectious disease have existed for a long time and we have, during this period, developed a relatively high resistance or “herd” immunity.
Improvements in our standards of sanitation have in recent times reduced the opportunities for dissemination of parasitic infections. Considerable numbers of our population have never been exposed to some of them. The “herd’ immunity has in consequence been reduced to a lower level, and there has been a relative increase in the proportion of those individuals whose inheritance lacks the ability to respond to infection by developing an effectual resistance.
The Australian native, evolving in a different environment free from these parasites, has developed no immunity. At the same time, he has with safety acquired practices of insanitation conducive to wide and heavy dissemination of infection, should it be introduced.
Entry of the white race into native country has led to the concentration of natives in fixed communities, a mode of life for which they ae singularly unadapted. In settled communities, the native’s accustomed neglect of sanitary precautions imperils the safety of both races, by creating conditions of squalor calculated to produce heavy infection.
Introduction of infection by white or other agency finds the native highly susceptible, and the environment admirably adapted to free dissemination. Rapid passage of infection through the susceptible natives may be expected to increase alike the virulence of the organism and the dose to which associated Europeans will be exposed. Either or both these factors may overpower normal resistance in the white population – a resistance already lowered by years of sheltered existence in a more sanitary community.
Hitherto, these diseases have been held in check in the Northern Territory, by sparseness of population, limited and infrequent communication, and the effectual quarantine imposed by respect for tribal boundaries. These factors are now largely inoperative – tribal boundaries have been broken down, there has been a very considerable increase in white population, and modern means of communication are rapid and numerous.
In the result amoebiasis, dysentery, malaria, hookworm, leprosy and tuberculosis are attaining an incidence in the native population imperilling the social and economic development of the Territory.
To aver the probability of these disease becoming permanently endemic in tropical Australia, well planned measures of local control must be applied. Success will depend not only on provision of a reliable means for the safe disposal of human waste, but upon inculcating tin the native population the habit of scrupulously using these. There can be no expectation of complete control until every individual is brought to a full awareness and acknowledgement of his responsibility, and until he can be trusted, automatically and without conscious through, to apply the basic preventive measures on all occasions.
Deficiency Diseases
Prevention of the disease included in the second group of our classification demands instruction of the community generally, in the broad principles determining healthful living in settled communities. The individual, for example, must have some knowledge of the nutritional requirements of the body, the available sources of these, their proper preparation, and the proportions in which they should be consumed.
None of the diseases of either group is susceptible of complete control except by the ordered behaviour of the individual himself. The time when prevention could be attempted by restraint imposed upon his person is already past. There is now no alternative to training of the native individually and collectively in the measures of prevention he must himself apply, developing in him at the same time a full consciousness and acknowledgement of his responsibilities to the community.
Control of the insect borne and contact group of infections demands identification and treatment of the carrier. This will imply a degree of liaison and co-operation between the individual native and the health authority, which can only be expected in a thoroughly enlightened and well disposed people.
The native must thoroughly understand the reasons for the obligations imposed upon him, and willingly accept them. The education necessary for this purpose will undoubtedly excite in him a social consciousness and a critical faculty. These in turn must inevitable lead to resentment and subversion if there is any racial discrimination to be discerned in the social structure – the living standard of both races must be raised to a common level.
The only available and effectual method of assuring the physical capacity of the labour force in the Northern Territory is one which, unless applied with enlightenment and courage, may lead to reluctance in the native to undertake responsibility in a community in which he enjoys no full share of the privileges. In the event, we will be denied the second component requisite for efficiency in a labour force.
If the native is to acknowledge and discharge in full his responsibilities to the community, he is entitled to expect and to receive the privileges of citizenship in their entirety. We reach, therefore, the inescapable conclusion that the native race must be assimilated and integrated individually and collectively into the white social structure, if the social and economic order in the Territory is to be preserved and advanced.
The cost of the native’s education and the initial cost of the facilities for his enjoyment of a higher standard of living must be met. The expense may not be small, and it may continue for a longer period that we might wish. However that may be, the cost must be unstintingly borne. This is no charity promoted by a quixotic benevolence, nor by a compassionate impulse to redress past wrongs, real or imaginary. It is an insurance premium inexorably demanded of us by self-interest, importunate and unashamed.