By Linfa Wang and Nola Wilkinson
Throughout history, infectious diseases have arisen unexpectedly and swept through human populations with catastrophic effects, like the Black Death and syphilis. We still face health threats today from diseases like AIDS, SARS and Hendra – though we don’t yet have a daily disease forecast like this one:
Most emerging infectious diseases come from wild animals which can carry the infection without life-threatening results. But when these diseases infect humans, the consequences can be fatal.
More and more health professionals are recognising that the health of humans and wild and domestic animals is linked, both subtly and inextricably. If the role of rats as disease carriers had been understood in medieval times, plague might not have spread so widely.
In recent times transmission of diseases from animals to humans has had devastating effects, such as the twentieth century pandemics caused by HIV (which came from African chimpanzees) and influenza (Spanish flu is likely to have travelled from birds to humans). Recently, our research team found that bats are a natural reservoir for lethal viruses including Hendra, Ebola and SARS.
We’re addressing these emerging threats to human health in our One Health research initiative. By looking at how viruses interact with their human and animal hosts, we’re developing tools for the diagnosis, surveillance and prevention of these diseases. Our research is focused on the development of new vaccines, anti-viral therapeutics and disease-resistant animals.
For instance, in 2012 we launched the Equivac vaccine, which protects horses from infection and thus prevents transmission of Hendra virus from horses to humans. Vaccines can block the transmission of infection, regardless of whether humans or animals are vaccinated.
We’re also working on potential therapeutic agents like monoclonal antibodies which are administered after infection, as well as anti-viral drugs which can either block entry of the virus to the cell and prevent the virus from replicating or prevent its maturation and release from infected cells.
These developments can help break the chain of virus transmission and limit the impact of new diseases in our closely interconnected and highly mobile world.
Learn more about our work in animal health.
On-call 24 hours a day, seven days a week, diagnostic scientists at CSIRO are ready to respond should an emergency disease outbreak occur.
They could test 10,000 samples per day in an emergency, but as standard delivery, CSIRO scientists at Australian Animal Health Laboratory (AAHL) in Geelong, Victoria, test more than 45,000 samples for 55 terrestrial and 40 aquatic animal diseases every year.
However, new infectious diseases, such as new strains of avian influenza, pose a constant threat to the health and wellbeing of animals and humans and pose a risk to Australia’s environment, industries and trade.
According to AAHL’s director Dr Kurt Zuelke, researchers are focused on reducing the threats of exotic and emerging animal diseases and, for example, are on standby with over 650 different tests covering a diverse range of animal species. “AAHL researches diseases of national importance found in livestock, aquaculture animals and wildlife, including those that can pass from animals to people,” Dr Zuelke said. “Our scientists are a front-line defence who help protect the country’s billion dollar livestock and aquaculture industries from disease threats on a daily basis.”
They play this defence role through performing diagnoses, establishing surveillance to monitor movements and emergences and if required, responding to animal disease emergencies. Better understanding diseases to develop diagnostic tests, vaccines and treatments is also crucial and CSIRO AAHL scientists lead the world on bat and insect-borne disease research. This is important for animal and human health as bats and insects are natural reserviours of a range of viruses and cause many of the world’s infectious diseases in both animals and humans.
Malaria and dengue, for example, are harmless to mosquitoes; blue tongue virus is harmless to midges; and Hendra, Nipah, and Severe Acute Respiratory Syndrome (SARS) viruses are harmless to bats – but all can be lethal to humans. AAHL also helps to train veterinarians in other countries to reduce the disease risks to Australia and is an official collaborating centre for capacity building in Southeast Asia. Recently, teams have visited Vietnam, Cambodia and Laos to train local veterinarians in disease diagnosis and testing techniques in their efforts to control and eradicate diseases such as FMD, classical swine fever and avian influenza. Importantly, this international work means Australia is more prepared with better threat assessments, surveillance and management options for many foreign diseases.
This article originally appeared in our 16 May Rural Press insert (pdf).
You can see what else we’ve been up to in our Rural Press Inserts Archive.
Part of the Biosecurity Series
By guest blogger Professor Peter Doherty
It’s no big secret that we’re citizens of an increasingly globalized planet where ideas, information, goods and services get around very fast. One of the downsides of this brave new world is that the same is true for pests and pathogens.
The security services, customs officers and quarantine regulations/officials protect Australia from such invasions as much as possible, although given the volume of trade and human movement, stopping bad things at the borders can only be part of any effective strategy.
There’s also a need for continual environmental monitoring to make sure that nothing dangerous slips through which could compromise Australia’s agricultural industries, wildlife and natural environments.
When it comes to biodefence against invading viruses, bacteria, insects, plants, marine parasites (on the hulls of ships) and so forth, we have layers of operation that function both at the Federal and State level.
This is, of course, where the wonderful high security CSIRO Australian Animal Health Laboratory (AAHL) comes into its own, providing the essential diagnostic tools and facilities for safe studies of deadly viruses in animals that are unique to the South-east Asian region.
Apart from its service to the veterinary world, AAHL has also pioneered studies of bat-borne viruses like Hendra and Nipah (active to the North-West of Australia) that can transmit to people from infected horses and pigs respectively. These are classic cases of the “One Health” view CSIRO takes that stresses the intimate interplay between animal disease and human disease. Apart from the Henipaviruses, AAHL also has the facilities that allow CSIRO researchers to study the avian influenza A viruses, that are a looming threat to both domestic poultry and people.
The new CSIRO Biosecurity Flagship pulls together research capability from across CSIRO together with a broad range of collaborating centres and groups. Sharing information is vital for such activities. Clearly, Australia cannot afford to have “silos” and artificial barriers that in any sense compromise our biological security. Of ongoing concern are the hi-path variants of the avian influenza H5N1 viruses that continue to circulate in wild and domestic birds (and occasionally infect and kill people) in the countries to the north-west of Australia. While we’ve avoided that particular threat so far, the situation requires constant monitoring.
I’ve said nothing about plant, insect and fish pathogens, but there are many diseases of key species, such as bees, trout and salmon that we have so far managed to keep at bay.
The new CSIRO Biosecurity Flagship is a great step in the right direction, and we need to continue doing all that we possibly can to ensure the long-term health and wellbeing of all the life forms that inhabit our extraordinary and unique country.
Join the Conversation: #bflaunch
About the Author
Peter Doherty trained initially as a veterinarian and shared the 1996 Nobel Prize for Physiology or Medicine for discoveries concerning our immune defence against viruses. He published the non-fiction book “Sentinel Chickens: What Birds Tell Us About our Health and our World” in 2012, and his new book “Pandemics: What Everyone Needs to Know” will be available in Australia from October.
Follow Peter on twitter: @ProfPCDoherty
Part of the Biosecurity Series
By John Lowenthal and Andrew Bean
Zoonoses are diseases that have the ability to spread from animals to people, and they include some very well known diseases such as tuberculosis, flu and rabies, as well as some less familiar newcomers such as the Nipah and Melaka viruses.
In recent times zoonoses have accounted for more than 70 per cent of all emerging diseases, including H7N9 and H5N1 avian influenza, SARS, and MERS. What’s interesting is that a great deal of these zoonotic viruses that now pose a problem for humans appear to originate in either bats or poultry.
This highlights our need to understand not just what is happening in the human, but also what is happening in the animal. Wild animals such as bats and migratory water birds are the natural ‘reservoir’ hosts for many zoonotic infections and little is known about how they carry these viruses without showing signs of disease.
Other animals, including horses, pigs, chickens and even people are ‘spillover’ hosts, meaning they are highly susceptible to these viruses, and infection is usually deadly.
The recent growth and geographic expansion of human populations and the advance of agriculture into wildlife habitats has meant that now, more than ever, there is a greater risk of emerging infectious diseases being transmitted to people from wild and domesticated animals.
In addition, the impact of climate change has resulted in disturbances in eco-systems and a re-distribution of disease hosts and carriers. Increased global travel means a greater likelihood that new infectious agents will rapidly spread amongst the human population.
The World Health Organization has warned that the source of the next human pandemic is likely to be zoonotic, and that wildlife is a prime culprit. While the current list of known emerging infectious diseases is a major concern, it is the unknown virus lurking out there, with a potential for efficient human to human transmission that may pose the biggest pandemic threat.
A rapidly spreading lethal airborne zoonotic virus would, of course, be a major concern. You may remember the 2011 movie Contagion, which showed a fast-moving epidemic and the struggle to find a cure and control the panic. The ABC’s Catalyst story Virus Hunters also demonstrates the threat of quickly spreading diseases, and looks at the research our scientists do in the high containment facilities at the Australian Animal Health Laboratory.
If we want to fight these emerging threats and come out on top, we need to take a different approach to what we have done in the past and integrate medical, veterinary, ecological and environmental research.
This is what we refer to as the One Health approach – a combined approach to animal, human and environmental health, and the idea that we can all benefit from working together to value and solve the health problems of the world and reduce the risk of the next pandemic.
We believe it’s important to study and compare the disease in both the natural and spillover hosts. For example, understanding the differences between the immune systems of domesticated and wild animal hosts and comparing them to people is crucial for identifying the underlying disease mechanisms involved in zoonotic infections, and for developing new strategies for disrupting their transmission to humans.
This has important implications for predicting, preventing and controlling spillover events, and for the development of new therapeutics, vaccines and diagnostics.
Improving knowledge, prevention and treatment of zoonoses is the focus of the One Health research that we’re undertaking with our national and international partners, and within our unique high containment facility at AAHL– the world’s most sophisticated high containment facility. Focusing our research efforts in this area will assist in facilitating the development and application of effective and sustainable community health strategies. There is a growing view that a One Health approach will be critically important for our preparedness for the next zoonotic pandemic.
Join the Conversation: #bflaunch
About the Authors
John Lowenthal is Theme Leader for A One-Health approach to Emerging Infectious Diseases, CSIRO Biosecurity Flagship
John’s research is in the area of veterinary health and immunology, including studying the innate immune responses to viral diseases, assessing the ability of immune modulators such as cytokines to enhance resistance to disease and improve vaccine efficacy, using RNA interference to modulate disease-resistance, development of novel therapeutics for zoonotic viruses (H5N1 flu, Hendra virus) and the development of disease-resistant animals.
Andrew Bean is Stream Leader for Animal Biosecurity, CSIRO Biosecurity Flagship.
Andrew is an immunologist working to improve animal and human health with a ‘One Health’ approach. He joined CSIRO’s Australian Animal Health Laboratory in 1998 and the emphasis of his work is now on the innate immune response and the therapeutic and immuno-enhancing qualities of cytokines with the potential to improve health. His current research areas include avian influenza, Hendra virus, immune molecules and receptors, developing and assessing antiviral therapy, vaccines and adjuvants and therapeutics.
Part of the Biosecurity Series
By Gary Fitt, Director of CSIRO’s Biosecurity Flagship
When our biosecurity scientists introduce themselves to people outside the organisation and say their job is to help to protect Australia from nasty pests and diseases, they’re normally met with a puzzled expression. Soon the puzzlement turns to awe, and is followed by questions like ‘You mean you get to wear those big suits like Dustin Hoffman in the Hollywood thriller Outbreak?’
While some of our scientists work in high containment laboratories, kitted out in special protective ‘space suits’ to research deadly diseases, our work in biosecurity is much broader.
Biosecurity threats extend beyond infectious diseases to include weeds, invasive animals and insects. These all have the potential to devastate our crops, livestock and farming profits, our environment and even human health.
Historically, Australia’s strong quarantine measures and geographic isolation have protected us from some of the most serious impacts posed by exotic pests and diseases circulating around the world, but the movement of plants, animals and people across the globe and a changing climate are placing pressure on Australia’s future ability to protect itself from exotic pest and disease threats.
To address these challenges, we’ve reorganised our biosecurity related research activities into our new Biosecurity Flagship (you can find the full details in the brochure) to bring scale and connectivity to help Australia prepare for and prevent the spread and impacts of pests and diseases.
What’s a Flagship you ask? In a nut-shell it’s a large-scale research program which uses world-class science to deliver powerful solutions that tackle Australia’s major challenges and opportunities. This new flagship focuses our research across animal, plant and environmental science to more rapidly develop solutions to address Australia’s major biosecurity challenges.
Australians are aware of the damage that diseases, weeds, invasive animals and insects can inflict on crops, livestock, properties, farm profits and on human health. Biosecurity is all about preventing or keeping the impact of these threats and outbreaks to a minimum. Through research, we are working to reduce the risk of pests and diseases entering Australia, as well as improving the effectiveness of our mitigation and eradication responses.
We’ve traditionally tackled wildlife, animal and human diseases completely separately, but what we’re doing now through the Flagship’s integrated activities is taking a ‘One Health’ approach to understanding how these viruses spread between wild animals, livestock and people, and how to reduce the risks or be prepared for rapid response.
For instance, to deal with zoonotic diseases (those that can pass from animals to people), we’re adopting a more coordinated approach to understanding the multidimensional links between wild animals, livestock production, the environment and global public health.
CSIRO’s One Health approach has already been successful with the development of a horse vaccine against the deadly Hendra virus. Flying foxes carry the disease, although they are not affected by it, and the virus is lethal when transmitted to horses and from infected horses to humans. By working together, we realised that there wasn’t much we could do to reduce bat populations, and vaccinating people would be too expensive and too lengthy a process. We identified the horse vaccine as the most direct and effective strategy for the protection of both people and horses, breaking the chain of virus transmission from flying foxes to horses, and then to people, and protecting the horses themselves from a devastating infection that would otherwise most likely lead to their death.
The improved coordination of biosecurity research through the Flagship will enable us to better safeguard public health, the environment and the economy into the future. It will also greatly assist other countries as they too strive to deal with the pests and diseases that continue to spread globally and threaten general health.
Biosecurity is a system of shared responsibility across layers of government, which needs a statistically sound understanding of risk, pathways of entry, optimised surveillance and rapid diagnosis. Working with national and international research bodies, and the operational agencies responsible for delivering biosecurity, we will work across all these issues to jointly tackle biosecurity threats head on.
Next Thursday marks the official launch of the Biosecurity Flagship. To celebrate the launch, over the coming week we will feature a series of blog posts highlighting some of the Flagship’s activities.
We’ll also be featuring a special post from our guest blogger, author, Nobel Laureate and 1997 Australian of the Year, Peter Doherty.
Join the Conversation: #bflaunch
About the Author
Dr Gary Fitt is Director CSIRO’s Biosecurity Flagship, and is focused on protecting Australia from the biosecurity threats and risks posed by serious exotic and endemic pests and diseases.
By Jayden Malseed
They say a picture’s worth a thousand words, but we’re hoping these brightly coloured images can tell an even bigger story.
At first glance you may think the image below is part of an octopus tentacle, or maybe the underside of an alien spaceship from the 1996 movie Independence Day, or perhaps even something else entirely.
Now this isn’t just your ordinary microscope. Costing roughly $750 000, the microscope is designed to focus on fluorescent colours that have been ‘tagged’ to specific components, which then show up on a big computer screen, giving us these incredible pictures.
The green highlights are the cells that have been infected by Hendra, while the blue highlights are the cell nuclei. To create this picture an antibody is dyed fluorescent green, which then attaches to the viral proteins, effectively colouring it green.
The vital research, led by microscopist Dr Paul Monaghan, uses these images to study the cell biology of Hendra virus. The confocal microscope, which is located within the high containment facility at our Australian Animal Health Laboratory in Geelong Victoria, helps Paul and his team better understand the virus, and to be able to answer questions such as why it attacks certain cells, and what it does when it gets to a cell.
“We’re developing a deeper understanding of the virus by using the microscope and the images, and if we can pinpoint a specific stage in the virus lifecycle and say to ourselves ‘this is the point we need to stop it’ then that would be enormous”, Paul explained.
The two images to the right are slightly different from the first. Where the first was a section from a kidney, these are taken from cells growing in tissue culture. We have also labeled two virus proteins: one red and one green.
They demonstrate how the Hendra virus has infected the cells, and after 14 hours has fused those cells together to form what is called a syncytium. The green/blue round circles are the nuclei – normally one in each cell – but the rest of the cell is relatively unaffected.
After 24 hours, the infection has progressed and newly made virus proteins are gathering at the edge of the cell (next to the black areas) to form new viruses. The red and green proteins are now together and can be seen as an irregular orange line at the edge of the cell.
These images allow Paul and his team to study the virus at different stages of its lifecycle, and and will be incredibly helpful for future research with Hendra virus and other related viruses that threaten the biosecurity of our animals, people and environment.
This research is part of our wider program of work on bats and the viruses they carry.
The last 30 years have seen a rise in emerging infectious diseases in humans, of which more than 70% are zoonotic. Zoonoses are diseases that normally exist in animals but have the potential to transmit to humans. They can be caused by many different infectious agents including bacteria, fungi and viruses.
Zoonotic infections have always been a part of the human disease landscape and most have come from domestic animals. The long lists includes anthrax, tuberculosis, plague, yellow fever and influenza. But with changes in environment, human behaviour and habitat destruction, these biosecurity threats are increasingly emerging from wildlife species.
Although it was established over a century ago that rabies was linked to bats, the research community was surprised to find that the SARS virus – which claimed more than 800 lives and cost more than $80bn globally – emerged from bats to civets and ultimately infected humans in the wet markets of southern China.
The World Health Organization (WHO) and most infectious disease experts agree that the source of the next human pandemic is likely to be zoonotic and wildlife is likely the prime suspect. While much effort has understandably gone into preparations for avian influenza, the next deadly pandemic may be the result of a currently unknown zoonotic agent.
Since the identification of bats as the probable source of the SARS epidemic, the global focus on emerging infectious disease has turned to them to understand and ultimately predict the source of the next human pandemic.
In the last 20 years, a significant number of highly lethal viral diseases have emerged from bat species across the world. These include Hendra virus and Australian bat lyssavirus in Australia and Nipah virus in Malaysia and Bangladesh, where regular outbreaks reach mortality levels of 100%. Haemorrhagic fever viruses, including the feared and lethal Ebola and Marburg viruses, have also emerged from bats in Africa and Asia.
After crippling the globe in 2003 and 2004, SARS appeared to have vanished until last year when there was a deadly human SARS-like outbreak in Saudi Arabia. It killed six out of 12 infected patients and cases of infection continue to emerge. Known as SARI (severe acute respiratory infection), this infection has now shown the critical capacity to transmit from one person to another and, like its precursor, initial evidence supports its emergence from bats.
Zoonotic diseases in humans can take several different courses. For some, like rabies and West Nile virus, humans are “dead-end” hosts. That is, they transmit (spill over) from their animal reservoir (host) into humans but as there’s no subsequent human-to-human transmission, the disease is restricted from spreading.
Others, such as SARS and avian influenza, spill over to humans, cause disease and are able to transmit from person to person before being eradicated or “burning out” from the human population, leaving no residual infection except in its animal host.
The third are diseases such as HIV AIDS, which spilled out of primates decades ago and has persisted in the human population ever since. And measles and mumps, which probably entered the human population thousands of years ago and are somewhat controlled but still circulating.
It’s impossible to completely safeguard against zoonotic diseases but steps can and are being taken to limit the opportunity for spill-over events through monitoring and rapid response when and where they do occur.
Controlling zoonotic diseases and protecting our animals, people and environment from increasing biosecurity threats will not only take a global effort but a multidisciplinary one. It cannot be addressed adequately with traditional human medical strategies where disease is fought in the human population only.
If we are to prepare and respond adequately to the next zoonotic attack, the approach needs to be diverse, taking in medical, veterinary, ecological and environmental factors. The transition will be complex, but necessary if we are to protect the global community from zoonotic disease as best as we can. After all, the stakes are high.
The authors do not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article. They also have no relevant affiliations.