Here's one. A supervillain called Biohazard. He doesn't have any innate superpowers, he's just a disgruntled bioengineer and epidemiologist who got fired by the CDC for his questionable use and research of genetically-engineered superbugs. He makes use of his research by utilizing strains of synthetic bactera, fungi, and viruses, and inserting them into custom made firearms, bombs, and other forms of weaponry. He dons a specially-made hazmat suit which seals away all manner of pathogens, including his artificial diseases.