Says the person who dodged my initial questions.

[He's quiet for a few moments after that as he puts his thoughts in order.]

If it isn't a disease and it's something that's been done to us, we have every reason to not tell because we're trying to weed out the source. And the fourth, who suggested it might be an enchantment, will most likely not speak with you, so coming to a consensus would be difficult. Your allegiances mean they do not want contact.