Complex sentence: If silkworms get this microsporidium in their larval stage, there are no visible symptoms; however, mother moths will pass the microsporidium onto the eggs, and 100% of worms hatching from the infected eggs will die in their larva stage.
Split into simpler sentences: If silkworms get this microsporidium in their larva stage, there are no visible symptoms. However, mother moths will pass the microsporidium onto the eggs, and 100% of worms hatching from the infected eggs will die in their larva stage.