I doubt that you are losing them to the virus. Typically, the cricket virus kills the Acheta when about half grown, as a mass die off. This can modify somewhat, but only under pretty unique circumstances in our experience. In any case, when the die-off hits, it kills same-age crickets at virtually the same stage of growth, in about a 2-3 day window max.
I know of no cricket facility that, once infected, was able to eliminate the virus. Many have tried. The only few successes required an entire relocation of the business, with all new equipment, etc. Those that were able to stay in business did so by switching to the Gryllus, and then Gryllodes ssp.