SAC Symposium - New diagnostic approaches for bovine respiratory diseases - Kim Willoughby: Transcript
Ken Rundle: You are listening to an SAC podcast from SAC’s Herd Health Symposium held as part of the VET Trust’s CPD event at Stirling. This event was funded by the Scottish Government under its Veterinary and Advisory Programme or VAS.
Bovine respiratory disease or calf pneumonia remains a major disease of young cattle. Rapid and effective diagnosis is going to be central to the prevention and cure. New molecular techniques for diagnosis now offer opportunities. Kim Willoughby is Head of the Virus Surveillance Unit at the Moredun Research Institute.
Kim, what exactly are these molecular techniques? How do they work?
Kim Willoughby: Molecular techniques involve looking for virus genes rather than looking for the virus itself. Looking for the virus itself means that we have to grow in cell culture or use sophisticated cell culture techniques which are lengthy and can be prone to contamination. Molecular techniques looking for virus genes can be done in a rapid way and allow us to look for more than one pathogen or virus or bacteria at a time so these kind of techniques have flexibility as well as speed and efficiency.
KR: They have come on a long way.
KW: They have come on a long way. The technique which we currently use is called PCR which is a method for detecting virus genes and PCR assays have been around for 20 years probably. In the last 10 years the technology of real time PCR assays has allowed accurate quantification of virus genes which means we can tell how much of a virus is present and whether it is likely to be important in the cause of the disease that we are seeing.
KR: And this is the point, with these tests, it’s not just one disease you can pick up.
KW: No, that’s right. The tests I am talking about this afternoon are aimed to detect the 3 important respiratory viruses of cattle. Bovine respiratory cyncytial virus, infectious bovine rhinotracheitis virus and bovine parainfluenza virus 3 and we have plans to introduce other pathogens like mycoplasma or bacterial pathogens into this test.
KR: What is exciting you, as usual with a scientist, is the next bit, is the future.
KW: Yes, the future is very interesting. The technology at the moment means that it is possible to look for maybe 5 pathogens at once and we call this multiplexing, looking for more than one pathogen at a time, but the technology which is now coming on board in the human field has the capability to look for 20/30 pathogens at a time using slightly different techniques and keeping a watching eye on those for the veterinary field is very important.
KR: This means that you will be able to move these tests, not to the lab, but basically to the veterinary surgery, the veterinary practice.
KW: Actually there are some tests available already in veterinary practices though none of these are molecularly based. However, people have looked at the possibility of moving molecular based assays outside to the veterinary practice or possibly elsewhere and while the technology is there the portability of the technology isn’t excellent at the moment. However, there are always possibilities looking to the future for bringing the test closer to the patient rather than bringing the patient’s sample closer to the laboratory.
KR: But having done that, you still need someone to look at the results and recognise what’s the significant bit and what’s important. Just because you find something doesn’t mean to say you should worry about it.
KW: Exactly and that’s where your vet comes in. It is very important that you discuss disease outbreaks with your vet and also that the vet may need to discuss things with the laboratory in order to interpret the results of these very sophisticated tests.