That doesn't look like a disease to me, rather the workings of an insect of some kind. As long as there are only a few, I wouldn't worry about it. Passions draw in all kinds of insects, including some beneficials.

Where did you buy your passionfruit? I'm looking for the purple variety (the kind that grows in South America), but can't find it. Help

gama, tradewinds sells fresh passion seed. Scroll down a bit here, you may mean Giant granadilla, or edulis, I don't know...but they have seeds
http://www.tradewindsfruit.com/tropical-fruit-p-r/

i would go with Edulis flavicarpa -Lilikoi
it is yellow

supposedly the better tasting of them.

P Edulis is excellent as well...

nick the seed coat, and put in warm/hot (not boiling) water for 1 or 2 days.
they can take several weeks, even 2-3 months to germinate.
but, worth it !

and you can get Amythistina as a pollinator (read below)

http://link.springer.com/article/10.1023%2FA%3A1003099709021#page-1

seeds here or...
http://www.tradewindsfruit.com/passiflora-edulis-var.-flavicarpa-lilikoi-seeds

live plant below...

Here is a link that might be useful: http://www.amazon.com/Yellow-Fruited-Passion-Vine-Passiflora/dp/B00LCDCQ2Y/ref=sr_1_4?s=lawn-garden&ie=UTF8&qid=1403979442&sr=1-4&keywords=hirts+edulis