The basic design of an experiment is to change one variable at a time. You have to do the one variable first. Then you can look at the cumulative things.
We did a neat little twist with our one variable. We introduced the PRV into the sockeye salmon and the Atlantic salmon. After the virus established itself for several weeks, we took the oxygen level of the water and we progressively reduced it and reduced it and reduced it in a short-term period. Then we asked how well they tolerated the hypoxia. Well, if your blood and your heart are not very good, you're not going to tolerate hypoxia. You wouldn't try to climb Mount Everest, for example. We found that they were unaffected compared with the sham controls. We have looked at mixtures, but only in what I would call the shorter term.