Black Spot Disease Transfer From Snail to Fish

[Tavia]

I recently got black spot disease in my tank. All my guppies have random black moving dots. The last thing I added to my tank was a mystery snail and I have over 5, I’ve never had this problem. How do I kill the parasite in the fish and snails? They don’t have much online about snails and black spot disease. How do I even know if I successfully killed the parasite? Can they get black spot disease from mystery snails?