Zoa POX - What Causes it? Can It Spread to other Corals? (Should I just throw it Out)

It looks like I have Zoa Pox on one or two Frags.



I was wondering what causes this?



Will it spread to other Zoanthids like Brown Jelly can Spread from Frogspawn to other Frogspawn?



Should I just throw the Frags out to be Safe?



I have been heavily investing in Zoanthids over the last year and have spent a lot of money on them (I have around 50 different ones now).



I am very very scarred that I will loose all of them like I have lost all my Chalices and Acans in the past.



What should I do?