This is literally exactly what zappers already do.
In fact it's mostly all they do.
Zappers might kill some small weak bacteria here and there but larger parasites like worms are unaffected (I've zapped ants and they were completely unaffected, and ants are much smaller than many worms like Ascaris). Zappers do not kill worms directly. The current is just too weak to do that. It does however give your immune system a temporary supercharge, which can then lead to the worms' deaths, or at least make your body so inhospitable to them that they voluntarily leave. Hulda Clark herself wrote this in her final cancer book before she died. You can read excerpts in various places online, but the gist is:
"A positive electrical force that pulses up and down not only appears to kill tiny invaders, it also seems to energize your white blood cells to go on an all – out attack on your enemies: your parasites, your toxins, everything, in spite of their four blockers. In spite of benzene, PCBs, metals, and asbestos! For a time, your WBCs turn into Super-WBCs. That I why I recommend eight hours of zapping daily until you are well."
This is why zappers actually made my autoimmune condition worse sometimes. As did anything that stimulated immune cells, like vitamin C, zinc, echinacea (which made me feel particularly horrible). All of these caused me a very distinct pain in my lower back, just like the zapper. I've yet to see a single zapper manufacturer provide any sort of warning for people with autoimmunity, and that's pretty shameful and irresponsible.
This typically only happened with a zapper if I used it for more than 10 minutes at lower frequencies (below 5000 hz) though. Prolonged use was what made it harmful. Overall I can definitely say I wouldn't be alive today if it weren't for zappers. Had lots of close calls in which a zapper saved my life. Don't throw the baby out with the bath water - just because zappers don't necessarily do everything that's claimed about them doesn't mean that they aren't helpful. They are not a miracle cure, but they definitely help.