Monitoring and surveillance of new and emerging diseases has become a high priority.
As the natural world keeps shrinking in the face of an increasing human population, the chance of new pathogens developing into local epidemics and world pandemics grows.
Dramatic changes in global biogeography and the sheer movement of people and produce has increased the chances for new disease-causing agents moving rapidly and even crossing from one abundant species into another.
The ‘westernisation’ of Asia combined with its traditional culinary customs has been critical to the emergence of several important diseases that have crossed from wild animals, sometimes through domestic animals (like pigs and poultry) to humans.
Retrospective investigations of epidemic diseases occurring in humans and animals are important because they give us insight into the ways these new pathogens emerge and impact. Today, new diseases can go global remarkably quickly and citizen everywhere would now more aware than ever before of the disease threats for which we either don’t have effective prevention or cannot anticipate when and where they will emerge.
The weakest link
The world relies on global health organisations like the World Health Organization and the Office of International Epizootics (epizootics is a fancy name for animal disease epidemics) to alert its citizens of these threats. However these organisations are only as good as the reporting capabilities of the various member nations (and for that matter sub-national provinces & states). This has always been a weakest link in the effectiveness of disease reporting. Completely new diseases are always going to create a lag time between when an unusual illness or a spate of deaths occurs and when the actual cause is determined, For infections with long incubation periods that means the world might not realise the extent of the spread and the degree to which a new pathogen has established in the human population until years later. The classic example is the retrovirus that produces HIV-AIDS. It is the Out-of-Africa disease of our time. The cause of AIDS was only discovered in the mid-1980s and we still do not have an effective vaccine in 2005. Over 25 million people have died from HIV, nearly 500,000 people in South Africa alone died of HIV infection in 2002 alone and one in nine people in that country is infected – a staggering 5 million people.
The Human Immunodeficiency Virus (HIV) is now believed to have originated in East Africa as viral infection crossing from its animal host, the Chimpanzee to humans in the 1950’s. The exploitation of bush meats by humans was implicated. And the spread of this infection continues every day throughout the world. A hidden virus that was quietly minding its own business in Chimpanzees 5 decades ago, now a human to human life-threatening infection.
Fast forward to Asia in the late 1990s and recall Nipah virus, SARS and Bird Flu. In the case of Nipah virus over 100 humans mainly rural villagers & pig farmers died in Malaysia, Singapore and Thailand. This viral disease was transferred from fruit bats through domestic pigs to these unsuspecting humans. Some readers may recall Australia’s version of this disease – Hedra virus. It killed the Brisbane horse trainer, Vic Rail, and another man who undertook a post mortem on a dead horse. Again bats were the source of this infection; this time human were exposed through contact with horses.
Serious impact on Asian tourism
Sudden Acute Respiratory Syndrome (SARS), turned out to have serious impact on Asian tourism. Over 8000 people were infected by this ‘new’ coronavirus with approximately 800 SARS deaths worldwide. The short incubation period and the capability for spread to occur through close contact and droplet infection meant that once this virus had adapted to its new host – us – the pathogen could merely exploit the high contact areas like hotels, market places, airports and aeroplanes to literally go global in very short time. This new virus has been tracked back to the wildlife meat markets in South Guangdong Province of Southern China where its natural carrier host, wild civet cats were (until very recently banned) butchered in their thousands for human consumption. Interestingly the butchers and restaurateurs had antibodies to this infection and only seemed to develop mild clinical infections.
And finally to Bird Flu, the so-called H5N1 strain of the influenza virus. This virus was first picked up as a serious cause of poultry deaths again in South China and Hong Kong in 1996-7 but due to cover ups the seriousness of this disease outbreak kept the world’s animal health reporting bodies out of the picture until after it had spread and taken hold in many parts of south Asia. It was only after some very serious failures in containment and breakdown in disease control quarantine had occurred that the embarrassed Chinese government was forced to sack local officials and open the country to international expertise. If that wasn’t enough, Bird Flu has been back with a vengeance again in 2001 and 2003, 2004 and 2005. It cut a swath across SE Asia taking out literally 10’s of millions of chickens and ducks in Vietnam, Cambodia, Thailand, Malaysia, Indonesia and India (and these are just the reported mass slaughters!).
Lately the numbers of human bird flu cases has been rising; the worry being that this bird-adapted influenza virus will genetically merge with pig or human influenza strains to create a truly human-human influenza infection. This is the future flu pandemic scenario that health experts are dreading. If we are not prepared it could dwarf all SARS and Nipah and be on a par with Spanish flu pandemic of 1919.
What has this got to do with Tasmania?
Both SARS and Bird Flu were covered up Thailand as the government there tried to play down their impact, fearful of the tourist backlash. In contrast communist Vietnam was among the first countries in the region to contain and eradicate both diseases and remained open and transparent to international reporting and oversight.
What has all this got to do with Australia, let alone Tasmania?
The global and the local are inextricably connected.
Australia has also had significant outbreaks of ‘avian influenza’ – a different strain of the flu virus. They occurred in large poultry-growing areas NSW and Victoria and cost both industry and government millions to contain. Bat-rabies and morbilliviruses occur in Australian bats. Our national animal disease capability is quite good for diseases in domestic animals; it keeps us free of Foot and Mouth Disease and Mad Cow Disease. But the area where our capability is inadequate is with the new and emerging diseases within wildlife hosts.
Why bother…you ask? Well firstly, because our wildlife could suffer. An exotic disease could wipe some species out. Secondly, our wildlife may already have disease-causing agents that could affect us if we work closely with them or possibly eat them. Thirdly, our wildlife populations could become carriers of significant unwanted pathogens that affect our trade in animal products.
Indifference to feral cat control
And then there’s Tasmania. We pride ourselves on our wildlife. Too many for some farmers and foresters; they’re harvested and in some cases poisoned. There’s also some commercial harvesting of wild ‘bush tucker’ for human consumption (wallaby, possum and mutton bird). At the same time the state permits the broad-acre use of 1080 poison. Two decades ago Tasmania was one of the few sub-jurisdictions that had internationally-regarded research and monitoring of wildlife disease. It was a core business of its Department Primary Industry, Water & Environment. Today that capability is merely reactive to unusual wildlife incidents.
The chance for Tasmania to be a Centre for Wildlife Health Monitoring is there. Indeed we have several important diseases in our wildlife that warrant that investment. And the list is growing as our involvement drops.
Chytrid fungus infection – killing Tasmania’s frogs
Devil Facial Tumour Disease – killing Tasmania’s devils
Platypus Ulcer Disease – linked to declines in platypus numbers
Ross River Fever – carried by wildlife but affecting humans
Seal Tuberculosis – a potential cross over disease to domestic animals and humans
Toxoplasmosis – killing lambs, wildlife and humans (spread & maintained by cats)
Eastern Barred Bandicoots are easily killed by Toxoplasmosis, so our cats will either kill them through predation or through this protozoan disease. When Tasmania has no more barred bandicoots, remember the indifference to feral cat control in 2005!
A politician might look at this article and see it as alarmist – not to be taken seriously. A rational thinker might reflect on it, analyse it and see it for what it is……reality.
Tasmania’s rhetoric hasn’t equated with reality
For too long Tasmania’s rhetoric hasn’t equated with reality. The reality is the world is out there and it is also watching us. Despite the words in glossy government documents supporting Clean, Green & Clever and Disease-Freedom, we need to have the capability and the political will to protect these values through a commitment to an island biosecurity & biodiversity framework
You could say we’re in a deep malaise but don’t know it. What will it take?
Our devils are dying of cancer, our platypus and frogs dying of fungal diseases imported into Tasmania and our wildlife killed by feral cats and their diseases.
Let us all hope that politicians of all parties understand the long-term consequences for a ‘do very little- business as usual’ model.