Originally posted by Theov39 I am now storing it separately from my other lenses, BUT If I keep using this lens, can it 'spread' to other lenses if i use them on the same camera?
Despite tons of internet myths, the answer is no. Fungus spores are in the air all the time and most likely in all of your lenses already. The only way this could possibly happen is if the fungus lives long enough to develop fruiting bodies and then expels spores into your other gear. But since all your gear already has spores inside it really does not matter. And although I have handled, and disassembled, numerous lenses with fungus, I have never seen fruiting bodies inside a lens.
Fungus can only grow in the presence of moisture and food. If you get your lens wet you have moisture and perhaps a tiny bit of food, but not enough for the fungus to grow for long. In most cases, spores sprout and filaments grow until the water is used up then they die, never really living long enough to fruit and make new spores.
The only way to prevent fungus is to keep your gear dry. If exposed to moisture, dry it immediately using a dry box if necessary. And moisture does not only mean rain. Your can get condensation inside a lens by moving a cold lens into a warm, moist environment. Such as going from strong air-conditioning to the outside on a warm, humid day. Or into a warm, moist home from a cold outside excursion.