drsimpson
Not so new Member
Hi again
Jamie... IBD (Inclusion Body Disease) is an interesting one. Up until about 18 months ago the actual cause of "Inclusion Body Disease" was not actually known. It was thought to be a virus but no-one had actually found the virus that was thought to be involved. It was called IBD because affected snakes showed characteristic "inclusions" or "inclusion bodies" in the cells of the brain and other tissues. These inclusions are darker staining small dots in the cells and are often associated with viral infections... but not always... and there are other causes of them. Different viruses cause different types of inclusions in different cells. Recent work has identified that the likely cause of IBD is a type of virus called an arenavirus. As such a viral identification test has now been developed and is being used to test snakes suspected of IBD. There is actually only one reported case of IBD in snakes in Australia and it was back in 1998. This diagnosis was based on the observation of inclusion bodies in the cells HOWEVER no virus isolation was performed (it did not exist!) and there is serious doubt as to whether these 2 snakes actually had IBD at all. Tim Hyndman has now tested 35-40 snakes in Australia based on this new technology and no snake has been found to be positive. In his opinion there is a small chance that IBD has been present in Australia but that its current status is unknown. The exact cause of the die off at the Australian Reptile Park hat you mention is still unknown though OPMV (now known as ferlavirus) was implicated. This would fit with the fact that ferlavirus does affect elapids amongst other species where currently no elapids have been detected with Sunshine virus (though only a small number of snakes have been tested).
Cement... " the test is valid wether the virus is being shed or not, and also while in the incubation period" Sorry but that statement is incorrect The current test is called a PCR test and detects the virus's DNA. If the test is positive then the snake has Sunshine virus HOWEVER if the test is negative it means one of two things. Firstly the snake may not be infected with Sunshine virus. The other reason for a negative test is that at the time the sample was taken the snake was not shedding the virus. There is mounting evidence that says that if a snake is infected it will shed the virus continually and therefore will always test positive but I know Tim would not come out and say that this was the case 100% of the time... because he simply does not have the data. In my experience with Sunshine virus if the snake is showing clinical signs (e.g. neurological disease, respiratory disease) then it will test positive. The issue is with those snakes that are not showing signs of the disease. I have been involved in a long term study with a number of other vets looking at snakes that have been diagnosed with Sunshine virus yet have shown no signs of the disease. There is still one snake of this group that has tested positive pretty much every month for over 2 years! This snake is a carrier and is still alive. This is the basis of why we recommend such long quarantine periods... there is the very real potential that a snake may be infected and show no symptoms for more that 2 years!!!! This is also why we recommend testing of new snakes coming into a collection because it can greatly reduce the length of the quarantine period required.
We also have no idea what the incubation period is on the virus so there is no way to say if the snake will test positive during this time... we don't know what this time is!
You are correct is saying the Sunshine virus causes inclusion bodies... but so does IBD, ferlavirus, bornavirus and a whole heap of different viruses. Sunshine virus and IBD are caused by COMPLETELY different virus and are most DEFINITELY NOT ONE AND THE SAME. This has been proven absolutely conclusively at looking at the DNA sequence of the viruses involved. They are very, very, very different viruses.
Wokka "Aren't they all a death sentence"... yes and no. The fact is that all these viruses are nasty and probably ultimately kill the snake. How long they take to do so and how they do so caries considerably. To be honest most of the affected animals are euthanased before they actually die of the virus. As I wrote above there is the possibility that a snake with Sunshine virus can actually live quite a long time with the virus and show no symptoms. If that snake was part of a larger collection then I would counsel the owner along the lines of euthanasia because it has the real potential of infecting the other snakes. If that snake was on its own or part of a small collection then euthanasia would not necessarily be the only option. It would be up to the owner to make the decision.
Jamie... actually the viruses we are talking about (i.e. IBD, Ferlavirus and Sunshine virus) can all now be detected in the living animal. No longer do we have to only diagnose on post-mortem. As for a vaccine that is still some way off but ultimately that is what Tim is working towards. There is still considerable work to be done. He now has a pHD student working on some other aspects of Sunshine virus and this will hopefully lead to further advancements. Watch this space... for at least the next 5-10 years!
Hope this information is useful.
Regards,
Dr Shane Simpson
Karingal Vet Hospital
Jamie... IBD (Inclusion Body Disease) is an interesting one. Up until about 18 months ago the actual cause of "Inclusion Body Disease" was not actually known. It was thought to be a virus but no-one had actually found the virus that was thought to be involved. It was called IBD because affected snakes showed characteristic "inclusions" or "inclusion bodies" in the cells of the brain and other tissues. These inclusions are darker staining small dots in the cells and are often associated with viral infections... but not always... and there are other causes of them. Different viruses cause different types of inclusions in different cells. Recent work has identified that the likely cause of IBD is a type of virus called an arenavirus. As such a viral identification test has now been developed and is being used to test snakes suspected of IBD. There is actually only one reported case of IBD in snakes in Australia and it was back in 1998. This diagnosis was based on the observation of inclusion bodies in the cells HOWEVER no virus isolation was performed (it did not exist!) and there is serious doubt as to whether these 2 snakes actually had IBD at all. Tim Hyndman has now tested 35-40 snakes in Australia based on this new technology and no snake has been found to be positive. In his opinion there is a small chance that IBD has been present in Australia but that its current status is unknown. The exact cause of the die off at the Australian Reptile Park hat you mention is still unknown though OPMV (now known as ferlavirus) was implicated. This would fit with the fact that ferlavirus does affect elapids amongst other species where currently no elapids have been detected with Sunshine virus (though only a small number of snakes have been tested).
Cement... " the test is valid wether the virus is being shed or not, and also while in the incubation period" Sorry but that statement is incorrect
The current test is called a PCR test and detects the virus's DNA. If the test is positive then the snake has Sunshine virus HOWEVER if the test is negative it means one of two things. Firstly the snake may not be infected with Sunshine virus. The other reason for a negative test is that at the time the sample was taken the snake was not shedding the virus. There is mounting evidence that says that if a snake is infected it will shed the virus continually and therefore will always test positive but I know Tim would not come out and say that this was the case 100% of the time... because he simply does not have the data. In my experience with Sunshine virus if the snake is showing clinical signs (e.g. neurological disease, respiratory disease) then it will test positive. The issue is with those snakes that are not showing signs of the disease. I have been involved in a long term study with a number of other vets looking at snakes that have been diagnosed with Sunshine virus yet have shown no signs of the disease. There is still one snake of this group that has tested positive pretty much every month for over 2 years! This snake is a carrier and is still alive. This is the basis of why we recommend such long quarantine periods... there is the very real potential that a snake may be infected and show no symptoms for more that 2 years!!!! This is also why we recommend testing of new snakes coming into a collection because it can greatly reduce the length of the quarantine period required.We also have no idea what the incubation period is on the virus so there is no way to say if the snake will test positive during this time... we don't know what this time is!
You are correct is saying the Sunshine virus causes inclusion bodies... but so does IBD, ferlavirus, bornavirus and a whole heap of different viruses. Sunshine virus and IBD are caused by COMPLETELY different virus and are most DEFINITELY NOT ONE AND THE SAME. This has been proven absolutely conclusively at looking at the DNA sequence of the viruses involved. They are very, very, very different viruses.
Wokka "Aren't they all a death sentence"... yes and no. The fact is that all these viruses are nasty and probably ultimately kill the snake. How long they take to do so and how they do so caries considerably. To be honest most of the affected animals are euthanased before they actually die of the virus. As I wrote above there is the possibility that a snake with Sunshine virus can actually live quite a long time with the virus and show no symptoms. If that snake was part of a larger collection then I would counsel the owner along the lines of euthanasia because it has the real potential of infecting the other snakes. If that snake was on its own or part of a small collection then euthanasia would not necessarily be the only option. It would be up to the owner to make the decision.
Jamie... actually the viruses we are talking about (i.e. IBD, Ferlavirus and Sunshine virus) can all now be detected in the living animal. No longer do we have to only diagnose on post-mortem. As for a vaccine that is still some way off but ultimately that is what Tim is working towards. There is still considerable work to be done. He now has a pHD student working on some other aspects of Sunshine virus and this will hopefully lead to further advancements. Watch this space... for at least the next 5-10 years!
Hope this information is useful.
Regards,
Dr Shane Simpson
Karingal Vet Hospital
