Cane Toads

The "Toad Virus GMO" Project

When Kevin Rudd became Prime Minister in 2007, a review took place of many scientific projects and several were cancelled. One of the cancelled projects was the toad virus GMO project. While there were probably economic reasons for this, we must loudly applaud this action. On first glance, voters might gasp at the seeming abandonment of an effort to control toads - but this was one project which really was too risky to ever contemplate. Our original arguments against this project remain here on this page so that you can understand why high-tech genetic engineering is NOT the way to get rid of this pest.

If you believe the Australian TV show '60 Minutes', this project is the 'silver bullet' that will magically remove all cane toads from the Australian environment. However, this is an illusion and there is a genuine risk that the disease being genetically engineered might become a pest itself . . . . to Australian frogs, reptiles and fish. In fact, it will not be possible to contain the virus within Australia so being in the US or Europe or Asia isn't going to afford any protection to your cold blooded wildlife either. Why do we feel so strongly against this project? We'll be glad to tell you!

Back in the 1980's and 1990's, the Australian government funded a variety of projects and studies which were meant to collect information that might be useful towards eradicating the cane toad from Australia. One of the projects involved sending some Australian ecologists to the toad's original sources (Venezuela and Brazil) to determine if there was a specific reason why the toad was not a pest in its native habitat. Aside from some parasites, nothing much was found that would explain what was keeping toad numbers in check. But Australian researchers did learn that there were ranaviruses/iridoviruses there and some of these were transported back to Australia where they are stored at the Animal Health Lab in Geelong.

Another of the projects which received copious funding at that time was to genetically engineer one of these Venezuelan ranaviruses into something which would kill toads and not kill frogs. We have been provided with a small stack of documents and we do know that the government decided to abandon the work in 1996 after they discovered that an Australian frog (the White-lipped tree frog, Litoria infrafrenata) could be easily killed by the GMO virus (GMO = genetically modified organism) they created.

Thinking 'that was the end of that', it came as a surprise to us to learn that a new, five year project at a cost of AUD $3.5 million was in well in progress and this project was back to using the same old virus drawing board - modifying a ranavirus (iridovirus) that was going to stop toads from metamorphosing while not causing disease in Australian frogs. This work is different from the previous virus tampering because the virus is not being used as a 'kill mechanism' itself but rather as a transport unit for a toad gene that has been modified to malfunction.

The chosen gene they've isolated in the toad is the one responsible for triggering a tadpole to metamorph and this gene was identified in the toad genome towards the end of 2003. The next intended step is to find a way to remove the ability of the virus to cause disease (this is called 'attenuating the virus' - (if indeed that is actually possible) and then to get the virus' DNA to accept and carry the modified toad gene. According to their plan, the virus will still reproduce itself with its passenger gene and spread in the environment but it won't cause disease. If we understand correctly, the virus is meant to merely deposit the toad gene in the body and, if the body is a toad, the modified gene will infect and/or replace the original gene already in the toad's DNA. Then the mutated gene is what will be reproduced and passed on to the offspring (toadpoles) and prevent metamorphosis. If it passes to a frog, in theory the toad gene won't do anything because it is a toad gene and the frogs don't have this same gene in them.

We are grateful that the Rudd government cancelled this project and feel this approach should never be contemplated again, especially when Australian frogs AND the cane toad are already in decline in this country and not attracting the sort of research that should be taking place.


Exposure to a virus can cause the target animal to mount an immune response and generate antibodies to that virus instead of getting sick (this is how flu shots work - by exposing a person to low levels of a virus to trigger them into generating antibodies). Antibodies to ranaviruses have already been found in Australian cane toads which means that those individuals have been exposed to a ranavirus here in Australia and they have put up a resistance to it.

  • So the first concern is that there are already virus problems here in Australia that have never even been isolated and characterised and the government wants to deliberately introduce another one.
  • The virus they want to modify is a ranavirus and they already know that toads are capable of generating antibodies to it. The myxomatosis virus they released is not effective against rabbits in wetter parts of Australia because it turns out that there already was a myxomatosis virus present in the wild and the rabbits had developed an immunity to it; when the 'modified' virus arrived in those areas, it didn't work (Surely the authorities knew that there already was a rabbit virus here before they released another one?)
  • The third problem is that ranaviruses are a threat to all cold blooded animals including frogs, fish and reptiles. The last time they 'played with' a ranavirus, they proved it could kill frogs and yet they persist in chasing a ranavirus as the first, last and only choice for this work.


Viruses are very fluid in nature and they change and adapt readily to environmental conditions and stresses. New strains of flu appear all the time - SARS had a new strain shortly after it was discovered and new human and animal virus problems are in the news regularly. Influenza A also has multiple strains (pathogenic and non-pathogenic). Some virus groups also skip over to different taxa when they mutate - Mad Cow disease only attacked cows until a new strain emerged that specifically targets humans called Crutzfeld Jacob new var..

There are two types of viruses: RNA and DNA. The Bohle Iridovirus (an Australian endemic) has been chosen for manipulation and it is a DNA virus. DNA viruses take a bit more nudging to mutate but they still can change. The bottom line is that no matter how much testing the government does on non-target species (and there are an awful lot of them to test - 220+ frog species, 200+ freshwater fish, all the snakes, skinks, geckos, turtles, etc.) before this virus is released, the government can never guarantee that the GM virus won't mutate once it is released into the wild.


During the field trials for two other pathogenic viruses that were engineered/released in Australia, those being myxomatosis (known as Rabbit Viral Haemmorrhagic Disease (RVHD) overseas) and calicivirus (distinguished as RCV or Rabbit Calicivirus overseas because of the number of calicivirus strains overseas that attack specific animals such as reptiles, humans, etc.) the virus being tested 'escaped' into the wild during both field trials. Our Curator has raised the question about improved security during field trials and clean up and contingency plans in case of an escaped pathogen on repeated occasions and has never received an answer other than "but we've learned so much since then". We do not understand how any field trial can be conducted using a volatile, environmental pathogen in the wild in the absence of any containment plans.


The planet is a living organism (GAIA) with circulating water and air systems as well as a lot of people and cargo movement. It would be physically impossible to contain a virus within Australia's borders. It is only a matter of time as to how long it would take for a virus to get from here to somewhere else. And a virus, being able to mutate according to changing environments, is sure to start adapting once it arrives somewhere different. The Australian government doesn't want rabbits here, for example, but that doesn't mean that other countries feel the same way. We have received reports of expensive efforts being made by the US, Spanish and Mexican governments to get rid of calici and/or myxomatosis (RVHD) because they DON'T want these viruses to wipe out their rabbits. For any country to introduce viruses to kill imported animals only leads to a "virus war" with the countries where those animals came from and the countries who welcome the importation of those animals.

Even if viruses were more stable, pathogens which are foreign to the areas they reach are more deadly because the animals have not evolved in conjunction with those diseases. For example, a virus that evolved in the Congo might cause incidental death rates to the animals that evolved with it in the Congo, but the same virus would be capable of massive death rates to the animals in Canada, or Thailand or Europe. Likewise, if the Congo started to import foxes or some other trade animal which is not normally found in the Congo, those imported animals would have no resistance to the local Congo diseases. The virus to be modified against cane toads (Bohle) is an Australian native and endemic virus so one could logically expect that if that GMO reached Europe, Asia or the Americas, toad species there will have no resistance at all to it and casualties would be high. There are endangered species of toads in these areas which already have threats to struggle against - a foreign virus could well wipe them out.


The sort of engineering that is being experimented with is a venture into new ground. We're not going to get involved in the philosophical or religous aspects of 'playing God' with the genetic fabric of life or creating new ways of destroying life. But the idea of introducing genes from one animal into others where they don't belong is a concern to many people. How do these researchers know what will actually happen when an outside gene is introduced to a foreign organism?


Our Founding President/Curator attended the CSIRO workshop on biological cane toad control in February 2004 and the information which was shared at that meeting can only be viewed as proof that the GMO virus will NEVER work. This is why:

  • The ranavirus they have chosen to work with is Bohle Iridovirus which is endemic to Australia. This is most likely the virus that cane toads here currently have antibodies to, so all the toads innoculated with antibodies already will be immune to the GMO virus.
  • Bohle has a temperature threshold! It is disabled at 34 degrees C and killed off at 42 degrees C. This means that it will be practically useless against toads in the entire Top End of Australia so another control mechanism will need to be found for the northern third of the country.
  • It is a desired criterion for biological control methods to be designed to phase themselves out as their target is eliminated which is not at all the case here. Once the GMO virus is out there, it will always be out there (even if there are no more toads) unless it is killed off by high temperatures.
  • A native virus is being used as the control mechanism and that virus is going to be weakened (attenuated) to the extent that it is incapable of causing disease -- but the GMO version is going to be released into the same areas that the wild type, original virus already lives. The ecologists at the meeting expressed the view that the attenuated (GMO) virus would not reproduce or spread properly since it was going to be in direct competition with its stronger, original self. Another worry was that the wild type and modified viruses could combine (see next point).
  • Another lovely thing that viruses can do besides mutuate is to recombine (this is not the same as recombinant) with other viruses to create entirely new ones. We know that cane toads are already dying here from a suite of problems that still have not been formally identified, so the notion of just dumping a new virus into what is already a disease "bouillabaise" is a really bad idea that can have unpredictable results. There can be no consideration of releasing a new virus into the environment until they have done a full survey of diseases which are already killing frogs and toads around the country.

We fully understand that the toad is pest in Australia and if you read through our other pages in this site, you will see that we promote targeted, humane disposal of this pest. But our opinion is that viruses are just too volatile to be playing with in a lab and then expecting that they are going to remain static and immobile in the wild. We are also dismayed that so much money is being dumped into this god-of-the-genepool approach that our genuine problems of diseases wiping out frogs (and toads) are again being completely ignored.

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