Okay; so Slice and lice.
By the way, for those who don't know, Slice is the trade name for a drug. Its generic name is emamectin benzoate. It's used in different countries and it's very effective at killing all life stages of lice when it works.
In other countries it's used multiple times each year. They use it every six weeks sometimes, for example. In B.C., as I said, we use it once a year normally.
Drug resistance can develop if there is a repetitive use of the product numerous times over short periods. If the drug is not effective at killing all the lice or all the bacteria, the animals that survive--the lice or the bacteria--then have the opportunity to pass on their genetic protection, resistance, of the drug to the offspring. So when the drug is used again, there's more protection. More animals survive and they keep passing on that genetics. It takes quite some time before drug resistance develops in a population of parasites or bacteria. Unfortunately, that is what we're seeing, failed treatments in other parts of the world where they are using Slice on numerous occasions.
Unfortunately, the lice...and again, we're talking here about the Atlantic Ocean louse, a very different animal from what we have here in British Columbia. That's what they're seeing, and as a result, they have to use alternate products to try to control their lice infestations on their fish.
Does that answer your question?