hello99,
Good morning (evening here).
The sevoro attributed to R’ Dessler is that chaza’l described the metzius in terms of perception, not science. Hence, lice may be killed on Shabbos despite the fact that we now “know” that they are not actually spontaneously generated. (As an aside, my rosh hayeshiva, zt’l, told me that a higher level of emunoh is to believe in chazal’s words literally.) The perception in the case of the lice would overrule the reality. In the case of the anisakis, the perception and reality (according to science) point to migration, not spontaneous generation. The psak of the Shulchan Aruch was never to be matir worms which seem to originate from the outside. The heter of the S.A. is not blanket, rather, a “stomo”.
You explained that you did not mean to say that this approach is radical (I still believe it is) but you did not answer my question; Do you think the anisakis worm is the worm (or at least included in the class of worms) which the Shulchan Aruch discusses, or is the heter based on a sevoro not reflecting the case of the S.A., but yet a compelling sevoro?