The deadly rabies virus was once common across Europe. A bite from an infected dog, wolf or fox could be fatal.
But then came a breakthrough: an edible vaccine. Since 1978, a billion baits containing the vaccine have been distributed by 30 European nations. Many European nations are now considered rabies-free.
Our research team has been developing edible bait vaccines for Tasmanian devils to protect them from devil facial tumour disease. This approach could be adapted to protect devils and other scavenging mammals from bird flu.
What’s missing is the right vaccine. Bird flu vaccines for mammals are still largely experimental. Getting a new vaccine tested and approved in time to be useful during this outbreak of bird flu would be very challenging – but not impossible.
The good news is that vaccine development took a huge leap forward during the COVID pandemic. Vaccines were being tested in humans about two months after genomic sequencing of the novel coronavirus.
Investing in new bird flu vaccines for wildlife will be useful to help prepare for future outbreaks.
How to dispense a vaccine
Tassie devils suffer from one of the world’s few known contagious cancers. When devils tussle and bite, they spread the tumour. Mortality rates are high.
In 2019, we began work on an oral bait vaccine to help prevent transmission of the disease. In fieldwork, we have tested use of a bait dispenser and several types of baits to increase how many are eaten by wild devils. Possums, quolls, pademelons and rats also eat these baits.
Our dispenser includes a microchip scanner so we know which animal likely took the bait and their current body temperature. Data is transmitted in real time. We don’t know if devil facial tumour disease or influenza would give devils a fever, but this system will help us find out.
In the lab, we developed a vaccine which stays stable in baits and can infect the cells of devil facial tumours. We hope to start small-scale trials in devils in the near future.
The smart bait dispenser we developed can detect Tasmanian devils.
Which species could this help?
We can’t vaccinate all Australian wildlife – and we don’t have the data to predict which Australian species will be most vulnerable to bird flu – or to future diseases.
Given this, it makes sense to try different vaccination methods and focus on threatened species. Official estimates suggest up to 10% of Australian mammal species are at high to extreme risk from bird flu.
We believe our approach could quickly be used for devils and scavenging mammal species if a new bird flu vaccine was developed. It could potentially work for colonies of birds which scavenge on land such as brown skuas – the first species found to have bird flu in Australia.
It’s important to protect scavengers, as these animals can get a massive dose of bird flu after eating from a carcass. This gives the virus more opportunities to mutate and adapt to their new hosts.
But our approach won’t work for seals, sea lions and other pinnipeds, as they do not eat while on land. It would also be challenging to use the dart guns used for animals such as bison and elephants. Hand injections or the use of needles on a pole could be an alternative.
We will need to find a solution. More than 13,000 southern elephant seal pups died after the H5N1 strain of bird flu arrived on Australia’s Heard Island last year. Testing confirmed the virus was present in carcasses.
But not all species are affected equally — infections were detected in six other bird and mammal species on Heard Island, but mass die-offs were seen only in elephant seals. An Australia fur seal has now died after infection.
Eastern quolls may also be at risk from bird flu.estivillml/Getty
Better vaccines urgently needed
To date, Australia has a single bird flu vaccine approved for emergency use in little penguins and captive birds.
This vaccine uses dead flu viruses that are designed to be injected. Unfortunately, this type of vaccine doesn’t work well for baits. We need to use weakened or modified live viruses, as they can more readily enter host cells to create an immune response.
In the United States, researchers have trialled a new vaccine which inserts a bird flu target into a weakened human virus. The vaccine protected mice from bird flu and induced a similar immune response in cattle. This approach is similar to both our Tassie devil tumour vaccine and a highly successful US rabies bait vaccine. This vaccine is generally distributed by aircraft with no follow up booster drops.
Oral rabies vaccines have been hugely successful despite the fact we don’t know how many baits each wild animal eats. Some may eat several and others none. To make sure this approach is safe, Canadian scientists tested much stronger doses on key species and found no ill effects. In the US, an exhaustive review found the approach was safe and effective.
Approving new vaccines for animals often takes years. Authorities often include strict dosing requirements. Both of these may have to change if we are to tackle bird flu in time.
The success of edible rabies vaccines suggests it’s worth making dose schedules more flexible. Vaccine development, too, could be sped up.
If we want better options to tackle bird flu and future wildlife diseases, we need to start now.
Andrew S. Flies has received funding from the Tasmanian Department of Natural Resources and the Environment, Wildcare Tasmania, Animal Control Technologies Australia, the Australian Research Council, Save the Tasmanian Devil Appeal, Wedgetail Foundation and UTAS Holdings.
Prithul Chaturvedi has received funding from the Menzies Institute for Medical Research (PhD Top-up Scholarship) and Save the Tasmanian Devil Appeal.
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We share our planet with millions of plants and animals.
This variety of life is known as biodiversity, a term encompassing everything from microscopic genes to entire ecosystems, such as deserts and vibrant coral reefs.
Places that support a wealth of species are known as “biodiversity hotspots”. South America’s tropical Andes region – which has the world’s largest variety of amphibian, bird and mammal species – and the coastal forests of eastern Australia are just two examples.
Our new study suggests biodiversity hotspots are emerging in new, and in some cases unexpected, locations.
So why is this happening? And what does it mean for species across the globe?
Spotting a hotspot
Scientists generally agree there are 17 megadiverse countries worldwide, including Brazil, Indonesia, India and Australia. But even within their borders, there are regions that are particularly rich in species, such as the Amazon rainforests of Brazil and Ecuador.
Finding biodiversity hotspots relies on scientifically describing the key characteristics of each individual species that occurs in a particular place. This includes identifying the features that distinguish a new species from all other known species, before giving it a formal and unique Latin scientific name.
The problem is there are many species western science hasn’t even discovered. Research suggests about 80% of the world’s plants and animals are yet to be formally studied. This is true even for well-researched vertebrate groups such as mammals, birds and reptiles.
For instance, each year researchers discover more than 2,000 new vascular plant species, which are distinguished by a range of features such as their special tube-like tissues. However, studies show as many as 100,000 more plant species remain unknown to science. And of the mammal species we know about today, one in ten were discovered only after the 1990s.
Our research suggests the discovery of new species is altering where we understand biodiversity hotpots to be located, including here in Australia.
In our new study, we examined discoveries of land-based species over 100 years to find out how they may have reshaped our understanding of global diversity patterns.
To do this, we identified when and where species were first found for each decade between 1920 and 2020. In the end, we collected data on more than 9,700 species of birds, 5,200 of mammals, 8,600 of reptiles and 7,200 of amphibians.
Our results suggest we’ve found and named nearly 40% of land-dwelling species over the past century. Most of these species discoveries have occurred in tropical regions such as the rainforests of Brazil, Ecuador and New Guinea. This aligns with the well-established pattern that polar areas, such as the Artic and Antarctica, typically have fewer species than tropical locations.
New Guinea’s montane forests – where plants grow on the slopes of mountains – had high discovery rates of new mammal species. When it comes to reptiles, Australia is a standout. The number of known reptiles nationwide has more than doubled over the past century, rising from 376 species in 1920 to 933 in 2020.
Our research suggests discoveries of new species are leading to the emergence of several biodiversity hotspots including Indonesia, the central Andes of South America and the island nation of Madagascar.
One-third of areas previously known for their rich amphibian life have been replaced by new amphibian hotspots, including the tropical forests of south-east Asia and the montane forests of the Andes. We observed a similar trend in reptiles. Roughly 20% of formerly recognised hotspots are now overshadowed by our new knowledge of regions with even higher reptile diversity, including the savannas and shrublands of northern Australia.
Understanding where biodiversity hotspots are, and how they are changing, is vital for conservation.
Our research suggests emerging biodiversity hotspots for reptile and frog species are increasingly in cooler environments, including the little explored cloud and montane forests of the Andes. However, by making these forests drier and warmer, climate change is threatening the survival of many newly discovered species.
These emerging hotspots are also vulnerable to deforestation and land clearing. Without major and immediate conservation action, the species living in these places will disappear, potentially before scientists even discover them. This is known as a “dark extinction”.
Protecting our biodiversity hotspots matters. But we cannot save species we don’t even know about, so we must invest in field surveys and taxonomy projects that lead to new species discoveries. Otherwise, these rich ecosystems will keep losing species that science never had the chance to name.
David Lindenmayer receives funding from the Australian government, the Victorian government and the Australian Research Council. He is a Fellow of the Australian Academy of Science, the National Academy of Sciences, the American Academy of Science, the Royal Society of Victoria and the Royal Zoological Society of New South Wales. He is a Councillor with the Biodiversity Council and a member of BirdLife Australia.
