Focus On Freeport #8: An Unwelcome Guest
No errata for this one (so far!), just a couple of comments [which has turned into an index only tenuously related to Focus #8]:
The DM must decide whether PC spellcasters must learn the detect disease spell from an NPC or will be freely given it by their gods when needed. Requiring spell research (DMG, p. 42) after the epidemic breaks out is almost certain to be a case of "too little, too late."
Clerics of level 5+ seem to be rare in Freeport (Sister Gwendolyn is 8th, K'Stallo is only 4th), so remove disease may be difficult to obtain if the PCs do not have the spell themselves (Clr5+, Drd5+, Brd7+, Rgr11+). Note that paladins are likely to be quite rare in a town as lawless as Freeport, but their remove disease ability (level 3+) would be invaluable in fighting the wraiths and the plague.
Freeport: The City of Adventure includes the following NPCs who may have access to remove disease:
Brd7+ [requires changing spells known]: Arias Soderheim (p. 26).
Clr5+: Sister Gwendolyn (p. 25), Asha Sante (p. 34), Golmon (p. 43), Father Mayhem (p. 93), Mother Loralee (p. 94), Brother Wilford Vinely (p. 95), Peg-Leg Peligro (p. 96), K'Stallo (p. 107; advanced to Clr6).
Drd5+, Pal3+, Rgr11+: none.
Denizens of Freeport includes the following NPCs who may have access to remove disease:
Brd7+ [requires changing spells known]: Celeste D'Arran (p. 18), Harcourt Horkel (p. 46), Laria Syrtis (p. 53), Zako Sebesteyen (p. 96).
Clr5+: Thirsty Knob (p. 63).
Drd5+: Rat (p. 73).
Pal3+: Moradon of Far Amrii (p. 59).
Rgr11+: none.
See also Crazy Mary's entry (Denizens, pp. 22-23) for more ideas on plague epidemics in Freeport.
Tales of Freeport includes the following NPCs who may have access to remove disease:
Clr5+: K'Stallo (p. 27), lizardfolk shaman (p. 59), Ssvalish (p. 60).
Brd7+, Drd5+, Pal3+, Rgr11+: none.
Black Sails Over Freeport includes the following NPCs who may have access to remove disease:
Clr5+: Cultist of Yarash (pp. 213, 245), Peg-Leg Peligro (p. 215), William Crimshavy (pp. 217, 251), Nador (p. 248).
Brd7+, Drd5+, Pal3+, Rgr11+: none.
On a vaguely related note, raise dead is only available to very few Freeport clerics (Clr9+: Mother Lorilee, Peg-Leg Peligro*, Crimshavy*, Nador*; *Black Sails), and none can cast resurrection (Clr13+) or true resurrection (Clr17+). (Raise dead is also available to Adp16+; none in Freeport.) Only Rat (Drd7+; Denizens) can cast reincarnate.