Is the "natural disease" phase of Contagion magical?

Question

The contagion spell afflicts the target with a disease for 7 days if they fail 3 saving throws while poisoned by the spell:

At the end of each of the poisoned target’s turns, the target must make a Constitution saving throw. [...] If the target fails three of these saves, the target is no longer poisoned, but choose one of the diseases below. The target is subjected to the chosen disease for the spell’s duration.

Since this spell induces a natural disease in its target, any effect that removes a disease or otherwise ameliorates a disease’s effects apply to it.

The duration of the spell is 7 days, which conventionally means that the spell's magic remains for the full 7 days and could be detected, dispelled, suppressed by anti-magic, etc. However, the description also specifies that the spell "induces a natural disease", which makes it sound as if the disease might be non-magical once it has been (magically) induced. Which interpretation is correct? Is the "natural" disease induced by contagion magical or non-magical?

Answer 1

The disease is magical

The Sage Advice Criteria for what counts as magical include both

• Is it a spell? Or does it let you create the effects of a spell that’s mentioned in its description?
• Is it fueled by the use of spell slots?

So, generally the effects of spells are magical without needing to say so. There are exceptions, for example if the spell is instantaneous, but creates something that then is permanent, but this is not the case here. A more specific statement in the spell description that an effect is non-magical could also override the general rule that spell effects are magical.

Neither is the case here. The target here is subject for the disease for the duration of the spell, so the disease is not the permanent effect of an instantaneous spell, and it does not say it's not magical. So it is magical. You could dispel magic the spell, and the disease would end.

The spell can also be ended by curing the disease, or the effects can be lessened by abilities that work on natural diseases. The sentence about the spell inducing a "natural disease" expresses that this is not a special kind of magical disease that is immune to such effects.

Answer 2

It's magical

The only aspect of the spell that can last any more than the poisoned condition is the disease itself. Therefore the duration must be the time that the spell forces the diseases to remain on the patient, after witch it would stop inducing the disease and patient would be fine.

If the intention was to make the induction of the disease be non-magical, we would need the duration of the spell to be "Until 3 saves are succeeded or failed" after which we would need to follow rules for natural progression of the diseases (which incidentally, does not exist)

Note that the rules also state effects that cure or remove diseases work as they would normally. So if you include a non-magical cure for these diseases those should still work.