Still working through this and the original paper, but while it can cause encephalitis in humans, it seems to be ubiquitous already anyway, and we don't seem to typically get it from insects. Setting aside the fact that you could swap malaria for almost any other infectious disease and humanity would be massively better off.

(Caveat: IANA Microbiologist and welcome corrections.)

It's one of those bugs that can opportunistically infect humans when their immune system is severely limited (i. e. end-stage untreated AIDS, unfortunate incident at a nuclear reactor). But that's a situation where almost anything will kill you.

(I once had a professor who likened it to a run-down house with young trees sprouting from the roof, adding that he'd be somewhat, but not extremely, surprised to find a immunocompromised patient with moss growing somewhere)