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This article was published in 1962
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INSTITUTE OF INSPECTORS OF STOCK OF N.S.W. YEAR BOOK.
"Crying Wolf" in Earnest
M. M. MacKINNON, B.Sc., M.R.C.V.S., Lecturer in Preventive Medicine, School of Rural Science, The University of New England
The words of Sir Walter Scott:
"Ill fares it with the flock
If shepherds wrangle when the wolf is nigh"
sound a much needed contemporary note of warning to the primary industry of Australia today. Britain's negotiations with the Common Market; new export markets for our primary products, increased levies for wool promotion; all these have the hollow ring of the wranglings of complacent shepherds over the hoped for profits of their flocks, while slinking closer come the wolves which will decimate their source of livelihood.
It is high time the Veterinary profession gave loud and urgent voice to a positive warning, and raised the alarm before it becomes too late. The threat of exotic and "new" diseases is not only imminent, but has the reality of a "fait accompli"; as demonstrated by diseases recently diagnosed in Australia.
Those who would like to assert that this is "Crying Wolf" needlessly, should take a close look at the mounting evidence. To begin with; is it true that "new" and/or exotic diseases have made their appearance recently in this country? The record of the postwar decades tends to be overlooked, probably because of the apparently innocuous nature and more or less limited occurrence of most of the newly-recognised diseases, which foster a sense of false security. Nevertheless, a list of "newly discovered" diseases in Australia includes: Infectious Equine Anaemia, Atrophic Rhinitis of Swine, Bovine Malignant Catarrh, outbreaks of bovine disease similar to the virus enteritis - mucosal disease complex, Infective Encepalitis of swine, Facial Eczema of sheep and, of course, the atypical Swine Fever outbreak of current notoriety.
Any attempt to pin-point accurately the time when these diseases were introduced into Australia, or to estimate how long they may have remained dormant before springing to light, could be instructive but would be superfluous to this review. If they proved to be recent introductions, then in fact are exotic diseases currently entering this country, and one can expect with confidence the appearance of other introductions. If, on the other hand, it was found that they had been introduced in some previous decade and had been smouldering undetected, one can justifiably wonder how many more diseases introduced as long ago (or more recently) are yet to come to light.
Nor is it wise to belittle these diseases, either, on the grounds of their relatively innocuous nature or because as yet they appear to have a limited distribution and incidence. Indeed, because of their very nature, the distribution of their infection may even now be growing apace. One has only to recall the examples of the growing awareness, throughout the world and in Australia, of the widespread presence and occurrence of Bovine Venereal Vibriosis to realise that it can be those very diseases, insidious and apparently innocuous, which are bleeding the economy of livestock industries annually at a staggering rate. Furthermore, arguments which point out the failure to date of these new found diseases to appear a outbreaks of any consequence, and which then infer that conditions in Australia therefore must be more or less unsuitable for them, fail to take into account the changes in husbandry and improvements in agriculture which are currently taking place. Enough is known of these diseases overseas to say that when conditions are favourable any one of them can become epizootic and cause serious losses. No one, however, can say yet with confidence what those favourable conditions are. How then can anyone predict an unaltered epizootiology of these diseases in a changing agricultural and pastoral environment in Australia?
Lessons derived from the epizootiology of certain diseases seem easily to be forgotten. Sudden explosive appearance of diseases are well known, and of these some seemed to be quite "new", while others were known previously only in sporadic and innocuous forms. Who can state from what source the '36-'37 Australian outbreak of Ephemeral Fever originated! Who would deny categorically that this disease smoulders in Australia today?
What reasons can be offered confidently for the explosive outbreaks of Blue Tongue in the western states of the U.S.A. after it had smouldered, not unnoticed but unrecognised, in Texas for two decades? Recently in the Union of South Africa a "new" cattle disease appeared as an epizootic in a newly developed irrigation area, and research indicated subsequently that this infection existed previously in the area both unnoticed and unrecognised. From whence sprang epizootics of Bovine Viral Rhino-tracheitis and Vaginitis; or of Mucosal Disease; or of Virus Diarrhoea; to mention but a few of the "new" diseases which have appeared in recent years. Whether one ascribes these appearances to mutations of viruses previously innocuous, or to the creation of conditions more favourable for increased epizootic behaviour of their disease coincident upon new husbandry developments, or to a combination of both these factors, the choice is cold comfort to those who confidently assert "It hasn't happened here all these years, so why should it happen now?"
However, it is not by these diseases that Australia is threatened most dangerously. The notorious animal plagues which this country always has feared, reinforced by newer but equally decimating diseases, will gain entry to this country sooner or later, and with disastrous effects.
To appreciate the reality of this worse threat, one must first review the situation of Australia within the world picture of livestock epizootics, and then examine the factors which will overcome our best efforts in quarantine precautions.
The global situation of livestock epizootics has shown a marked deterioration in the post-war years in that diseases once confined have broken bounds and have spread with inexorable and devastating effects. The most serious outbreaks have escaped from the continent of Africa. Chief among these is Blue Tongue Disease of sheep, which spread into and over Spain and Portugal, where it seems to have come to a halt; possibly only temporarily, with its way barred by the Pyrenees. It also spread eastward through the Middle East, and continuing to travel steadily, has been causing serious losses recently in Pakistan. Following the wake of this disease come two others - African Horse Sickness and African Swine Fever. At the same time, within Africa, other diseases (for example. Rift Valley Fever) have broken out from their local confines and have appeared in areas once regarded free of them. Not only have well recognised diseases broken bounds but, as already mentioned, a crop of "new" diseases occurring as epizootics has been reported from the U.S.A. and Canada, as well as the U.K. and European countries. As an example, Atrophic Rhinitis of swine, once relatively obscure, became a world-wide disease in a matter of a few years.
Progress in the control of the well-known plague, Foot and Mouth Disease, has been disappointingly slow and ineffectual. This disease still rolls over Europe and Asia, and up and down the South American and African continents. Research discloses a growing multiplicity of different strains of this virus, with corresponding immunological individuality. Canada, which once enjoyed a similar freedom from this disease as does this country, experienced an unexpected and alarming epizootic recently. The U.S.A. is forced to send veterinary aid to southern neighbours to secure its own boundary from this plague. Countries of the Far East and South East Asia (as close as Indonesia) frankly live with the disease; relying upon its relatively innocuous nature in cattle populations in which it has been enzootic for a very long time.
The sole success in controlling a major epizootic animal plague seems to be in the greatly reduced incidence of Rinderpest in Africa and Asia. Once a plague more serious than Foot and Mouth disease, it is now of minor epizootic occurrence in large areas of the world where it once caused enormous losses.
At the side of this sombre picture stands the island continent of Australia, still free of these major plagues, but becoming increasingly vulnerable. The extent of, and reasons for, Australia's long enjoyed freedom from decimating disease are worth examining. One might concede that Australia has experienced freedom only from serious plagues of viral origin, and that in her history there have occurred (and still occur to a lesser degree) both major and minor epizootics of a very comprehensive range of the world's livestock diseases caused by bacteria and by protozoa. Bovine Pleuro-pneumonia, Anthrax, and Redwater of cattle are present still as reminders of the devastating plagues of the last century. Lesser plagues such as Brucellosis, Tuberculosis, Vibriosis,etc., have become widespread enzootic infections.
It is assumed, since the natural fauna is free of known plagues and since the original livestock introduced did not contract from them any strange enzootic infections, that this island continent was very fortunate in being plague-free from antiquity. Indeed It is fairly certain that nearly all the infective diseases of Australia's livestock were introduced.
The long sea voyages of the earlier days and the sources of imported stock, together assured Australia's freedom from the major epizootic viral diseases, but were not adequate protection from ubiquitous and hardier bacterial infections. Since the early days of introduction both of stock and of many of their diseases, the application of quarantine measures has succeeded in maintaining the country's freedom from major epizootics. What is the reason, then, for predicting the imminent breakdown of the system which has operated successfully for half a century? Why must we cry "Wolf" in earnest now; when quarantine restrictions virtually amount to a total embargo upon livestock imports?
Certainly this is not the time to infer laxity in our quarantine precautions when they have been tightened practically to their full extent, but it is high time to examine what is happening at the gaps which quarantine cannot close no matter how rigidly enforced. It is through these gaps that disastrous introductions will come with ever-increasing certainty as the volume of traffic through them mounts rapidly.
Human traffic, least subject to quarantine, has always been a "gap". Once a negligible volume and conveniently "disinfected" by time consuming sea transport, this traffic has not only increased in volume steadily but, with the advent of speedy air transport, now arrives with whatever infective contamination it has chanced to acquire still fresh upon it. Furthermore, whereas in time past this traffic was confined to narrow sea lanes mainly directed to and from the Motherland, and travellers infrequently set foot further afield, today the wider interests of travellers, together with the vast network of airways, has increased enormously both the number and the global distribution of places whereon this traffic has set foot. The chance of travellers becoming contaminated from a worldwide range of infections is provided, and the likelihood of the introduction of such contamination increases as the volume of travellers arriving by air mounts up.
To-day, Sydney's overseas air-terminal serves a volume of human traffic second only in this country to the port of Sydney, and within the next five years expects to serve twice the present number of airlines each with a steadily increasing number of services per week. With every new passenger who steps off an airliner from overseas Australia acquires, as it were, another ticket in a macabre lottery of which the prize is a disastrous outbreak of a plaque such as Foot and Mouth disease. Circumstantial evidence suggests strongly that it was just in such a way that Canada "bought" her unexpected outbreak. Quarantine, no matter how stringent, is powerless to prevent this happening.
The same increasing frequency of chances enhances the likelihood that among the human traffic, and destined for country areas, there will arrive individuals apparently healthy but incubating infection of one of the Zoonoses; say, of Rift Valley Fever, or one of the viral encephalitides, or of Brucella melitensis. More serious still is the increasing likelihood that travellers will introduce infection-carrying Insects; enclosed, for instance, accidentally, but so easily in baggage where there is protection from the insecticidal spraying carried out on incoming aircraft; and from which they are later released unharmed. In some such way will Blue Tongue cheat the quarantine precautions.
One can add to these hazards the persistent trickle of apparently innocuous smuggling (or so it seems to the unenlightened) which introduces edible but potentially infective animal products such as salamis,etc., and native "leather" souvenirs which are practically rawhide. Since a greater opportunity for this type of introduction now occurs at airports, where in order to suit the "tempo" of fast travel associated with modern airlines, customs examinations have become more rushed, another gap has been widened dangerously.
The evidence is more than adequate to raise the alarm in earnest; and time is fast running out. It is the responsibility of the Veterinary profession to point out to the shepherds of the national flocks and herds that decades of security have caused them to grow careless, complacent, and unprepared to meet the new and imminent threat. There is a tremendous lee-way to catch up. Can this be accomplished before the first major plague arrives? If not, then unprecedented disaster awaits this country.
The shepherds require convincing of the inadequacy of their defences and trained manpower. Major epizootics cannot be fought by veterinarians so thinly distributed either in terms of hundreds of square miles, or of hundreds of thousands of animals per individual oversight. In Canada's attack upon a confined outbreak of Foot and Mouth disease a "blitz-group" of seventy veterinarians was mustered; more than the total number of government veterinarians in all N.S.W. Even if the whole veterinary profession were to be mobilised compulsorily it would amount to a very small army of men, many of whom were trained long ago; and nearly all completely inexperienced in the type of specialised warfare into which they would be thrown. How many of them have been sent overseas (and how frequently) to observe and gain experience in up-to-date methods of diagnosis and control of these diseases? It is known that the aggressors will be viral diseases. How many veterinarians specially trained in Virology exist in this country, and how many of the Veterinary Schools possess the staffs, facilities and special laboratories for training such men?
Consider the terrain and conditions under which such warfare must take place; where stock-proof boundary fences and complete musters are grim unreality; where droves of wild fauna (about whose susceptibility to these diseases so little is known) wander at will; where at times travel becomes impossible. Consider also the lessons of past viral insect-borne diseases in this country among totally susceptible populations; the speed with which Ephemeral Fever spread; the devastating mortality of Myxomatosis. These make contemplation of the advent of Blue Tongue distinctly unpleasant, even although this disease is controllable by vaccination. How soon could this country produce and administer the multi-million doses of vaccine which will be necessary? How long did it take to do the same in the urgent control of poliomyelitis with Salk Vaccine in a much smaller human population? Could the national flock be protected before being wiped out?
Shepherds! Wake up! Look to the safety of your very sources of livelihood! The wolves are indeed circling closer!