[quanaco]

Is there a hard rule yet in 5th edition for how many hits you need on Assensing for telling if someone is HMHVV infected or a host to an insect spirit? I mean I know the dual-aspected types would show up as such immediately barring metamagic abilities, but would 3 hits be enough to at least say infected/bug host? I'm guessing that five hits could give you specifics like ant or wasp host, or any given strain of HMHVV if I'm reading the table right, but what could you tell with fewer hits?

Edit: Assensing not apperception. Crosstalk in my head from too many RPG systems.

[8-bit]

It took me a moment to understand what you were talking about. It's not Apperception, it's Assensing.

I would go with 3 hits for noticing, 4 hits for general cause, and 5+ hits for specific cause. Barring Metamagics.

[jim1701]

As far as spirits go there is this:

SPOTTING SPIRITS IN VESSELS
Noticing materialized spirits is easy, but spirits using Possession or Inhabitation are harder to detect. To spot a spirit possessing/inhabiting a vessel, an observer must succeed in a Perception +  Intuition [Mental] (6 –spirit’s Force) Test.  Success also reveals clues as to what the spirit really looks like. At the gamemaster’s discretion, the use of a spirit’s powers may create an effect similar to a shamanic mask, thus adding a +2 dice pool modifier to the Perception Test.

As far as astral perception goes I would say the threshold should be almost automatic barring masking type meta-magics.  For example, an inhabiting spirit with Flesh-Form gets both Aura-Masking and Realistic Form making that critter hard to spot.  I think you could still use the basic rule I quoted to determine if a body is inhabited but if it can disguise itself the GM should make it pretty tough to get any details on the spirit itself.

[ScytheKnight]

As for Infected.. it is a disease... most strains will cause immediately noticeable mutations so you're not even going to need Assensing to identify them as Infected. For those that still look 'normal' I'd then use the standard Assensing table in regards to the health of the target, adjusted for any metamagics they may be using to try and hide the signs of infection from their Aura.

[Shaidar]

As far as spirits go there is this:

SPOTTING SPIRITS IN VESSELS
Noticing materialized spirits is easy, but spirits using Possession or Inhabitation are harder to detect. To spot a spirit possessing/inhabiting a vessel, an observer must succeed in a Perception +  Intuition [Mental] (6 –spirit’s Force) Test.  Success also reveals clues as to what the spirit really looks like. At the gamemaster’s discretion, the use of a spirit’s powers may create an effect similar to a shamanic mask, thus adding a +2 dice pool modifier to the Perception Test.

As far as astral perception goes I would say the threshold should be almost automatic barring masking type meta-magics.  For example, an inhabiting spirit with Flesh-Form gets both Aura-Masking and Realistic Form making that critter hard to spot.  I think you could still use the basic rule I quoted to determine if a body is inhabited but if it can disguise itself the GM should make it pretty tough to get any details on the spirit itself.

With Realistic Form this isn't even an option.

REALISTIC FORM
Type: P Action: Auto
Range: Self Duration: Special
A spirit with Realistic Form can be mistaken for a normal physical creature or object when it materializes, or it appears unremarkable when joined to a vessel. A spirit that appears as a metahuman would have a heartbeat and a regular breathing rate. A spirit that appeared as an object mimics the object’s normal functionality; for example, a toaster could be plugged into the wall to toast bread (though it would have no Matrix link, making it an antique toaster). The spirit is in no way disguised from the astral plane, but to physical observation appears to any senses to be a natural part of the physical world.
Note that spirits with the Materialization power normally only have one materialized form. Materializing spirits with this power can choose to appear using Realistic Form or their normal materialized form. A fire elemental can still appear as a column of angry flames but might also be able to appear as a beautiful woman.

So, assensing a Flesh Form Insect would be governed by the mechanics of the Aura Masking Power and the Masking Metamagic.

AURA MASKING
Type: M Action: Free
Range: Self Duration: Sustained
Sometimes a spirit doesn’t want someone to assense its natural aura. This power functions like Masking (p. 326, SR5) and Extended Masking metamagics. Use the spirit’s Edge in place of its initiate grade. The spirit can also hide its own use of powers on itself within the mask; only a magician who pierces this mask can see the spirit using such powers. A spirit can mask itself to look like another astral being, but it cannot try to pass itself off as a mundane being unless it is attached to a physical body or has the Realistic Form power (p. 198).

Masking: You learn to change the appearance of your aura (and astral form). You can make it look mundane, or make your Magic Rating look higher or lower by up to your grade. When someone tries to read your masked aura, the Assensing Test becomes opposed by your Magic + initiate grade—if they get any net hits, they see both your mask and your real aura. If you can use astral perception, you can even make your aura look like a different type (like a spirit or a focus—great for astral costume parties). You can also use this metamagic to mask the auras of as many of your bonded foci as your initiate grade.

So, the Opposed Test will Stack up as follows:
Assensing + Intuition [Astral] vs. Force + Edge