Maybe the local mosquitoes survived thanks to surviving human settlements, and then spread via stagnant water around the area.
They're deep into Silent Finland (though I have no information about what distances a mosquito would or wouldn't call "a marathon") and Reynir apparently did not meet any in "the capital" / Finlands int'l harbor, either, which should be on the rather large side of existing settlements.
Any arriving beasts are few and far between, and can't infect any of the resident animals. I wonder if for that reason they move on?
Hm. The rules stated in-comic say that beasts aren't
inclined to do much wandering, and don't have a "move on or
starve!" motivation
forcing them to. When I think about them having a nonzero chance of winding up on this Rash-free island, I'm primarily thinking along the lines of "washed into the lake in a storm and unwilling to just pop out some gills and fins" ...
I'm no mosquito expert, but at least some that bite birds also bite humans
The logic implied by Onni is that "
if they're willing to bite mammals and there are any infected within range, they'll randomly try to nom one of those sooner or later and promptly die", which makes it somewhat irrelevant who their
usual victims are.
The eggs in still water places.
... IIUC you're assuming that the Rash had come to the island
and gone again in between the eggs being laid and having evolved into an imago? Fat chance, given the near-immortality of grosslings ...
Spoiler: math nerd talk show
I could not find any info whether female mosquitos lay but one clutch, or several. In the latter case, she does, of course, not first do all the bloodsucking of her lifetime and then start laying eggs if and only if she didn't die from chancing onto a rashed victim, so there's a nonzero probability that she gets to lay eggs even in an infested area, and the infestation is going to kill off the mosquito population only over several of their generations. But still, what Onni stated is that seeing even a single mosquito is proof that there's no Rash in the vicinity.
I think a lot of people would include echinoderms and acorn worms (Hemichordata) among the creepy-crawlies, and they're deuterostomes.
The problem with that is that "
deuterostome" (and thus the next-higher clade encompassing both,
nephrozoa) does contain all the critters people usually want to
not associate with "creepy crawly" and similar terms of endearment.
most people use "bug" in the broadest sense. I just get caught up sometimes in the futile crusade to reclaim "bug" for the Hemiptera.
So you're saying that that topic does not personally bug you?
Speaking of faces: I have had another thought, based on recent greater experience with face masks. Reynir must be wearing his 24/7, no?
Actually, no. Even if we assume that Minna will occasionally just not draw it
at all (in addition to half-transparent versions), it has been
established that Reynir is sometimes out and about sans mask. After all,
most grosslings have to
bite him to get him infected ...