Disease Manipulation – The ability to control diseases.
Infectious Lass (DC) has this power (Superboy V1 #201).
Host (Pathogen) thinks of the diseases that inhabit her body as her children in Mystique #8 (Marvel).
Disease manipulation is not a common superpower but disease is used as a weapon by super villains, most notably Ra’s al Ghul (DC) uses Ebola Gulf-A, nicknamed “The Clench” to almost wipe out all humans in Gotham City before Batman finds a cure. The Clench first appears in Batman-Shadow of the Bat V1 #48.
Stryfe (Marvel) creates a virus called the Legacy Virus that only effects mutants.
The alien Technarchy uses the transmode virus to transform organic matter into techno-organic matter that they can absorb as energy. If a member of the Technarchy doesn’t absorb the infected being then they instead turn into a techno-organic being slave (Uncanny X-Men V1 #300).
In Death Sentence by Titan Comics, a sexually transmitted disease gives the infected superpowers before killing them (Death Sentence #1).
Probably the most interesting comic disease is the Jigsaw Disease that appears in the Judge Dredd universe in 2000 AD #172.
Aliens – Astonishing V1 #49 (1956)
Plague Spewer – D&D 3.5 – Monster Manual III
Plague Wretch – Creature Collection I
Simak – Meta-Baron T3 Orne #8 (Humanoids)
Slarecian Language Virus – Creature Collection I
Spirit of the Plague – Creature Collection I
Touch Corrupter – Creature Collection II. Dark Menagerie
Viltrumites (Image) – Invincible #66
Wamp – Field Guide to Creatures of the Dreamlands
The Amazo Virus is a synthetic disease that grants superpowers before killing the host in Justice League-Injustice League V6.
In All-Star Batman V2 #6, Mr. Freeze (DC) explains how the ice core has a disease that will end life on Earth and of course he plans to use this disease for one of his mad plans.
Bloodmorel – DC Comics Presents-Superman Swamp Thing #85
Doomsday Virus – Superman V3 #31
Finn – 2000 AD #770
Marrashi – TSR 2145 Monstrous Compendium Annual Volume 1
Virus X – Action Comics #364
Rat of 12 Plagues (Marvel) in Iron Fist #77 (2018).
Next 133) Disease Mimicry