I doubt very much that this is a virus, most initial stage of the disease stagonospora. Tip: spray the plant with a solution benlate \ benomyl 1%. This part of the leaf is green will not, if the damage is small - can be cut off after spraying.

thanks.
I wiped the leaves with 50% peroxide(3%)+ water yesterday (found in posts) and brought the plant indoors to dry up the soil and isolated it in a very sunny window.
not sure I understood about the leaf. can I just cut it off to limit the infection. and then spray the other leaves?
the bulb doesn't have any red marks. so I would assume it's just the leaves that got it?
I will look for fungicide with benlate.
I've seen captan and thiomyl mentioned too.
but I only currently have Chlorothalonil (marketed as Daconil). could that be used too or not?
and I also saw recommendation to use systemic (imidacloprid), which I have and actually it is already in the soil. i'll add more. this is to prevent spread by insects?